Comparison of immunodeficiency and AIDS defining conditions in HIV negative and HIV positive men with haemophilia A

Caroline A Sabin, K John Pasi, Andrew N Phillips, Patricia Lilley, Margarita Bofill, Christine A Lee

Abstract

Objective - To investigate the hypothesis that high usage of clotting factor concentrate, rather than HIV infection, is the cause of immunodeficiency and AIDS in men with haemophilia.

Design - A comparison of AIDS defining conditions and CD4 counts in HIV positive and HIV negative patients with haemophilia matched for usage of clotting factor concentrate.

Setting - A comprehensive care haemophilia centre.

Subjects - 17 HIV positive and 17 HIV negative male patients with haemophilia A (age range 12-60 at beginning of study period) who had received similar amounts of clotting factor concentrate yearly over the years 1980-90.

Main outcome measures - Clinical events listed as AIDS defining in the Centers for Disease Control AIDS definition; CD4 Iymphocyte counts; death.

Results - Of 108 HIV positive male patients with haemophilia A, only 17 could be matched to an HIV negative patient. This was due to the much higher average usage of factor VIII in the HIV positive group. Between 1980 and 1990, 16 clinical events occurred in nine of the 17 HIV positive patients. No event occurred in the 17 HIV negative patients. In each pair the mean CD4 count during follow up was, on average, 0.5 x 10 to power 9/l lower in the HIV positive patient.

Conclusion - These data reject the hypothesis that high usage of dotting factor concentrate, rather than HIV infection, is the cause of immunodeficiency and AIDS in men with haemophilia.

Introduction

There has recently been debate about the pathogenic role of HIV infection in AIDS. It has been suggested that HIV is neither necessary nor sufficient to cause severe disease definitive of AIDS.[i-iv] On the basis that transfusion of clotting factor concentrates could be related to the development of AIDS-like diseases in haemophilic patients, it has been suggested that the use of factor Vlll concentrates is the "cofactor" essential for the development of AIDS in patients with haemophilia A.[ii]

We studied the effects of HIV infection on the development of conditions listed in the Centers for Disease Control AIDS definition and on the immune systems of a group of men with haemophilia A. In order to control for the use of clotting factor concentrates we performed a follow up study with HIV positive patients matched to HIV negative patients on the basis of concentrate usage.

Patients and methods

Between 1979 and 1985, 111 men with haemophilia registered at the Royal Free Hospital's haemophilia centre - including 108 with haemophilia A, one with haemophilia B, and two with von Willebrand's disease - became infected with HIV after treatment with contaminated factor VIII concentrate.[v,vi] Hospital records identified 152 men with haemophilia A who were registered at the centre in 1979, when infected batches of factor VIII started to be used, who had remained HIV negative after repeated regular testing. Clinical events that meet the Centers for Disease Control AIDS definition are routinely recorded in all patients at the centre.

Computerised yearly total treatment records were available for each patient since 1980. At the end of 1990 all HIV positive patients at the centre were switched to monoclonally purified factor VIII concentrate.[vii] These concentrates seem to preserve the immune system of recipients,[viii,ix] though their effect on clinical end points is not clear.[x] As only HIV positive patients receive this treatment we focused on CD4 Iymphocyte counts and clinical events occurring before the end of 1990, when all patients received only intermediate purity factor VIII. We report separately clinical events which occurred in 1991-4. These data, however, should be interpreted with caution, as the patients may no longer have been comparable in terms of the factor VIII concentrate received.

Measurement of CD4 Iymphocyte subsets began at the hospital in late 1982, and CD4 counts are recorded for each patient at each clinic visit. In general, HIV positive patients are seen every three to six months and HIV negative patients every six to 12 months. The measurement of CD4 cells in this cohort has been described.[xi]

Eligible patients were 12 years and older at the start of 1980 and had at least two CD4 counts recorded during 1982-90. Patients aged below 12 were excluded, as CD4 counts decrease naturally from birth to 14 years.[xi] Hence by the time of the first CD4 measurement in these patients in 1982 all patients were aged 14 or older.

HIV positive patients were matched to HIV negative patients in two stages. Firstly, each HIV positive patient was matched for his median yearly usage of concentrate to an HIV negative patient whose usage was closest to and within 5% of that of the HIV positive patient. Secondly, the mean yearly amounts of concentrate received were compared in cases and controls and considered a good match if they were within at most 30 000 units. All matching was blind to patient outcome. Matching on the basis of both median and mean usage ensured that patients were treated similarly in terms of the number of years of treatment with concentrate and the overall amount of concentrate received. As most patients with severe haemophilia - and therefore the highest users of clotting factor concentrate - were seropositive to HIV, only a few matches could be identified. However, the patients who could be matched in this manner were comparable in their usage of concentrate.

Since August 1987 HIV positive patients at the centre have routinely been treated with zidovudine after the development of AIDS or, more recently, once their CD4 count falls below 0.2 x 1O to power 9. Since 1988 patients have also been given prophylaxis against Pneumocystis carinii pneumonia (with pentamidine or co-trimoxazole) and candidiasis (with fluconazole). Primary prophylaxis against both conditions is begun once the CD4 count falls below 0.2 x 10 to power 9/l.

Statistics - Paired comparisons between HIV negative and HIV positive patients were tested for significance with McNemar's test for the development of AIDS and the sign rank test for the mean CD4 count during follow up.

Results

Seventeen matched pairs were identified. There was wide variation in the patients' ages, though the distribution was similar in the HIV positive and negative groups. The patients' ages at the start of 1980 ranged from 14 to 60 years (median 26) in the HIV positive group and 12 to 50 years (median 20) in the HIV negative group. In almost all cases the mean yearly factor VIII usage was higher than the median (table 1), reflecting the skewed nature of factor VIII usage. In general the mean yearly usage of factor VIII was slightly higher in the HIV positive patients, though as a result of the matching procedure in no pair was the difference more than 30,000 units. One HIV positive patient (pair 1) seroconverted as a result of exposure to clotting factor concentrate received before the introduction of computerised treatment records in 1980. This patient did not require factor VIII subsequently.

Before the end of 1990 no condition listed as part of the Centers for Disease Control AIDS definition or death occurred in the 17 HIV negative patients. However, nine of the 17 HIV positive patients had developed AIDS by the end of 1990 and seven had died. Four of the seven patients died of AIDS deaths in the three remaining patients were due to pneumonia, cerebral haemorrhage, and cirrhosis. All other deaths in this group were due to AIDS related causes. Among the nine HIV positive patients with AIDS, 16 AIDS events occurred during the study period. No such events occurred in the HIV negative patients (P less than 0.01, McNemar's test) (table 2).

The figure shows the CD4 Iymphocyte counts of patients during follow up. Mean counts ranged from 0.07 to 0.70 x 10 to power 9/l (median 0.28 x 10 to power 9/l)in HIV positive patients and from 0.45 to 1.55 x 10 to power 9/l (median 0.79 x 10 to power 9/l) in HIV negative patients. On average, mean CD4 counts over the study period were 0.5 x 10 to power 9/l lower in HIV positive patients (P equals 0.0001, sign rank test; 95% confidence interval for difference 0.35 to 0.66 x 10 to power 9/l).

All nine HIV positive patients with AIDS received zidovudine. However, in seven zidovudine was begun only after an initial AIDS defining event. Three HIV positive patients received zidovudine but had not developed AIDS by the end of 1990.

After 1991 no deaths or conditions that would be AIDS defining in HIV positive patients occurred in the 1X HIV negative patients. Though there were no new incident cases of AIDS in the HIV positive patients, there were a further six AIDS events in patients who already had AIDS and a further six deaths in this group. ss

Table 1 - Median and mean yearly factor Vlll usage (units) and ages (on 1 January 1980) of 17 HlV positive and 17 HlV negative patients
	HIV positive			HIV negative
Pair No	Median	Mean	Age (years)	Median	Mean	Age (years)
1	0	0	20	0	0	35
2	2870	4539	14	2920	6483	24
3	8530	43874	60	8868	17676	14
4	10200	41430	37	9724	19415	45
5	10270	51207	50	10581	25330	36
6	10870	15045	18	11101	25365	25
7	15763	22097	14	16170	20856	29
8	17570	23001	26	17765	17550	18
9	28450	35017	32	28610	23714	47
10	29965	40480	21	30295	37880	14
11	37425	60791	29	37400	40753	25
12	38896	73576	20	38520	44177	20
13	39484	62874	24	39900	43146	13
14	40200	64779	16	40415	61456	50
15	59992	73169	43	60490	64687	12
16	92435	97964	41	91920	86704	18
17	101920	106371	56	104240	106359	16

Table 2 - Clinical events listed as part of Centers for Disease Control AIDS definition and deaths during 1980-90 in 17 HlV positive and 17 HIV negative patients matched for factor Vlll usage
Pair No	HIV positive	HIV negative
1
2
3	Died
4	Toxoplasmosis, died
5
6
7	Pneumocystis carinii pneumonia
8	Toxoplasmosis, mycobacteriosis, died
9
10	Pneumocystis carinii pneumonia (twice), Iymphoma, died
11	Pneumocystis carinii pneumonia
12	Oesophageal candidiasis, cytomegalovirus retinitis, died
13	Pneumocystis carinii pneumonia, oesophageal candidiasis
14	Pneumocystis carinii pneumonia, cytomegalovirus disease, died
15	Died
16	Wasting syndrome, Pneumocystis carinii pneumonia
17

Discussion

Though factor VIII concentrates have been implicated in immune modulation, several workers have shown that the immune response is only subtly affected by the infusion of these concentrates in HIV negative subjects.[xii,xiii] However, in general, the patients in these studies have mild haemophilia and do not receive anywhere near as much factor VIII as HIV positive patients, who more commonly have severe haemophilia. Consequently, the possibility that factor VIII causes some of the immune deterioration in HIV positive haemophilic patients has not previously been ruled out.

We matched patients on the basis of their average yearly factor VIII usage so that any differences in clinical events and laboratory markers could not be attributed to factor VIII usage. Though we made our matching criterion as stringent as possible, small differences remained in the amount of clotting factor concentrate received between HIV positive and HIV negative patients. In order to match more closely at both stages a much larger number of patients would be required. It is unlikely, certainly within the United Kingdom, that this amount of detailed information on factor VIII usage would be available for many more patients. The possibility that these differences might explain the differences in clinical events and CD4 counts must be considered.

This study included patients with a wide range of factor VIII usage, including some patients receiving very low amounts and some receiving very high amounts. If a 30,000 unit difference in mean yearly factor VIII usage explained the clinical differences it would be likely that at least some clinical events would occur in the HIV negative patients receiving the highest amounts of factor VIII. Furthermore, a dose-response relation might be expected in both HIV positive and HIV negative patients. This did not seem to be the case in our study. Consequently, it is unlikely that the differences in mean yearly factor VIII usage could explain the clinical findings.

By matching on the basis of concentrate usage we restricted our analysis to only 17 patient pairs. However, despite these small numbers we found a statistically significant difference in overall CD4 cell counts between HIV positive and HIV negative patients. The development of clinical conditions listed in the Centers for Disease Control AIDS definition was restricted to HIV positive patients (also a highly significant difference) despite the reported associations between factor VIII usage and opportunistic infections.[i,ii] The development of such conditions in patients thought to be HIV negative would prompt further investigation in addition to their regular HIV testing. Hence it is highly unlikely that any such conditions went unnoticed in patients known to be HIV negative.

RELEVANCE OF AGE AND OTHER FACTORS

Though the range of ages was similar, the median age of the HIV positive patients in our study was six years greater than that of the HIV negative patients. Age is associated with increased progression of HIV disease,[xiv] so the possibility that age differences led to the increase in AIDS conditions and deaths in the HIV positive patients should be considered. As the overall distribution of ages was similar, it is unlikely that a six year difference in median.age could explain such large differences in clinical events. CD4 Iymphocyte counts in uninfected patients remain fairly stable over the age of 14,[xi] so it is also unlikely that the age difference could have resulted in such large differences in the CD4 counts of the patients.

It might be expected that the introduction of high purity concentrates for HIV positive patients would lead to a reduction in clinical disease in these patients. But after 1991 a further six AIDS events and six deaths occurred in the HIV positive patients. No clinical events occurred in the HIV negative patients. Though these data should be interpreted with caution (as the patients may no longer have been comparable in terms of the amount of factor VIII received), they add further support to the finding that clinical events which met the Centers for Disease Control AIDS definition occurred only in patients infected with HIV.

Antiretroviral agents for HIV infection became available at the centre from 1987. In this study most of the HIV positive patients who received zidovudine did so only after an initial AIDS diagnosis. More recently some HIV positive AIDS free patients with CD4 counts below 0 2x 109/l received the drug. However, it is clear that differences in the patients' CD4 counts were apparent long before the counts dropped to this low level. Consequently, these data are not consistent with the suggestion that AIDS is caused by zidovudine.[iii,iv]

In conclusion, we have shown that in a group of haemophilic patients matched for factor VIII usage the development of conditions listed as part of the Centers for Disease Control AIDS definition was restricted to those patients who were HIV positive. Furthermore, CD4 counts were lower and more likely to decline in these patients. It is unlikely that differences in factor VIII usage, patient age, or zidovudine use can explain the findings. We conclude that HIV infection leads to progressive immune deterioration and AIDS irrespective of clotting factor usage.

Key messages

We thank Professor George Janossy and the department of clinical immunology for measuring CD4 Iymphocyte subsets. We also thank Professor Paul Griffiths and the department of virology for measuring antibodies to HIV.

Funding: CAS was supported by a grant from the Medical Research Council.

Conflict of interest: None.

HIV Research Unit
Department of Public Health
Royal Free Hospital School of Medicine
London NW3 2PF
Caroline A Sabin lecturer in epidemiology and medical statistics
Andrew N Phillips reader in epidemiology and biostatistics

Haemophilia Centre and Haemostasis Unit
Department of Haematology
Royal Free Hospital and School of Medicine
London NW3 2PF
K John Pasi consultant in haemophilia and haemostasis
Patricia Lilley nursing coordinator
Christine A Lee director haemophilia centre

Department of Clinical Immunology
Royal Free Hospital and School of Medicine
London NW3 2PF
Margarita Bofill senior research officer

Correspondence to: Dr Sabin.

i. Duesberg PH. Human immunodeficiency virus and acquired immunodeficiency
syndrome: correlation but not causation. Proc Natl Acad Sci 1989;86:755-64.

ii. Duesberg PH. AIDS epidemiology: inconsistencies with human immunodeficiency
virus and with infectious disease. Proc Natl Acad Sci 1991;88: 1575-9.

iii. Duesberg P.HlV and the aetiology of AlDS. Lancet 1993;341:957-8.

iv. Duesberg PH. AIDS acquired by drug consumption and other noncontagious risk
factors. Pharmacol Ther 1992;55:201-77.

v. Lee CA, Phillips A, Elford J, Miller EJ, Bofill M, Griffiths PD, et al. The
natural history of human immunodeficiency virus infection in a haemophilic
cohort. Br J Haematol 1989;73:228-34.

vi. Lee CA, Phillips AN, Elford J, Janossy G, Griffiths P, Kernoff P. Progression
of HIV disease in a haemophilic cohort followed for 11 years and the effect of
treatment. BMJ 1991;303:1093-6.

vii. UK Regional Haemophilia Centre Directors' Committee. Recommendations on
choice of therapeutic products for the treatment of patients with haemophilia A,
haemophilia B and von Willebrand's disease. Blood Coagul Fibrinolysis
1992;3:205-14.

viii. Sabin C, Pasi J, Phillips A, Elford J, Janossy G, Lee C. CD4plus counts
before and after switching to monoclonaI high-purity factor Vlll concentrate in
HlV-infected haemophilic patients. Thromb Haemost 1994;72:214-7.

ix. Seremetis SV, Aledort LM, Bergman G, Bona R, Bray G, Brettler D, et al.
Three-year randomised study of high-purity or intermediate-purity factor Vlll
concentrates in symptom-free HlV-seropositive haemophiliacs: effects on immune
status. Lancet 1993;342:700-3.

x. Goedert JJ, Cohen AR, Kessler CM, Eichinger S, Seremetis SV, Rabkin CS, et al.
Risks of immunodeficiency, AIDS and death related to purity of factor Vlll
concentrate. Lancet 1994;344:791-2.

xi. Bofill M, Janossy G, Lee CA, MacDonald-Burns D, Phillips AN, Sabin C, et al.
Laboratory control values for CD4 and CD8 T Iymphocytes. Implications for HlV-I
diagnosis. Clin Exp Immunol 1992;88:243-52.

xii. Schulman S. Effects of factor Vlll concentrates on the immune system in
hemophilic patients. Ann Hematol 1991;63 145-51.

xiii. Madhok R, Gracie A, Lowe GD, Burnett A, Froebel K, Follett E, et al.
Impaired cell mediated immunity in haemophilia in the absence of infection with
human immunodeficiency virus. BMJ 1986,293:978-80.

xiv. Phillips AN, Lee CA, Elford J, Webster A, Janossy G, Timms A, et al. More
rapid progression to AIDS in older HlV-infected people: the role of the CD4plus
T-cell counts. Journal of the Acquired Immuno Deficiency Syndrome 1991;4:970-5.

Commentary: non-HIV hypotheses must be studied more carefully

Peter Duesberg

Patients with haemophilia treated with commercial factor VIII and zidovudine are at risk of developing AIDS defining immunodeficiency diseases like pneumonia, candidiasis, and toxoplasmosis but not Kaposi's sarcoma or dementia. Their risk of these diseases is proportional to their lifetime dosages of factor VIII and cytotoxic DNA chain terminators like zidovudine.[i,ia]

Haemophilia specific AIDS diseases have been explained in terms of two hypotheses. A non-infectious hypothesis holds that the long term administration of immunosuppressive foreign proteins contaminating commercial factor VIII and zidovudine causes AIDS. An infectious hypothesis holds that HIV causes AIDS.[i]

Still no evidence for infection

Based on inadequate tests, Sabin et al reject the foreign protein-zidovudine hypothesis.[ii] However, their data and those of others actually support the hypothesis.

Sabin et al claim that HIV causes AIDS because all of their haemophilic patients had antibodies against the virus. But HIV cannot be enough for AIDS because six of their 17 HIV positive patients (table 2) remained healthy for 10 years. Likewise 12,000 out of 15,000 HIV positive American haemophilic patients have remained AIDS free since 1985.[i,iii]

Sabin et al observe that AIDS diseases occur, if at all, only five to 10 years after the appearance of antibodies to HIV. However, "viral" AIDS should occur within weeks after infection because viruses replicate exponentially. A single infected cell produces over 100 HIV virions within 48 hours,[iv] generating 10 to power 14 viruses within two weeks after infection - enough to infect every cell in the human body. Moreover, viral AIDS should be neutralised - not caused - by the antiviral immunity that is detectable in haemophilia.

By contrast, long time periods are required to accumulate pathogenic doses of foreign proteins via transfusions.[i] Because HIV is a rare contaminant of factor VIII, it seems to be just a surrogate marker for high dosages of foreign proteins. Sabin et al confirm this: ³Most patients with severe haemophilia - and therefore the highest users of: clotting factor concentrate - were seropositive to HIV...²[ii] Thus their results support the foreign protein hypothesis.

An appropriate test of the foreign protein hypothesis would compare HIV positive patients with HIV negative patients matched for the lifetime dosage of factor VIII. By contrast, Sabin et al matched patients for current usage. Plainly, a 60 year old and a 14 year old would not be an appropriate match (table 1)[ii]

The HIV hypothesis predicts the same pattern of AIDS diseases in haemophilia as in other AIDS patients, but Kaposi's sarcoma and dementia were not observed in the haemophilic patients studied by Sabin et al (table 2). However, the foreign protein-zidovudine hypothesis predicts the restriction to immunodeficiency diseases observed by Sabin et al exactly.

The HIV hypothesis predicts sexual transmission of AIDS. However, in the United States the wives of 15,000 HIV positive haemophilic men have only the normal background prevalence of AIDS defining diseases.[i,v]

Strong temporal evidence

HIV is now said to cause AIDS 10 years after infection, and infections by transfusions were stopped in 1985. Hence AIDS in patients with haemophilia should have peaked long before 1995. Instead, cases declined until 1986[i] and then sharply increased from 1987 both in the United States and in Britain when zidovudine and other drugs were introduced as treatment for and prophylaxis against HIV infection and AIDS.[vi,vii]

Zidovudine kills all growing cells, particularly fast growing blood cells, and therefore must cause immunodeficiency. Even the manufacturer acknowledges, "It is often difficult to distinguish adverse events possibly associated with zidovudine administration from underlying signs of HIV disease."[viii] An epidemiological study cited by Sabin et al directly confirms that zidovudine treated HIV positive haemophilic patients have a 4.5-fold higher annual AIDS rate and a 2.4-fold higher annual death rate than untreated controls.[ix] This explains why the morbidity of American[vi] and British [vii] patients with haemophilia has sharply increased since 1987, when most HIV positive haemophilic patients began zidovudine.[i,ia] Sabin et al confirm the zidovudine hypothesis, as "all nine HIV positive patients with AIDS received zidovudine" in addition to the "toxic" pentamidine,'° co-trimoxazole, and fluconazole.[ii]

The foreign protein hypothesis predicts that AIDS in patients with haemophilia can be prevented if not cured by using factor VIII that is free of foreign protein. Sabin et al endorse this: "These concentrates seem to preserve the immune system...." Indeed, not only were the immune systems of HIV positive haemophilic patients treated with pure factor VIII and no zidovudine "preserved" but their T cells increased by up to a quarter over three years - despite the presence of the hypothetical T cell killer HIV.[xi,xii]

Conclusion

The foreign protein-zidovudine hypothesis provides biochemically plausible candidates for pathogenicity - that is, large amounts of foreign proteins transfused over decades and DNA chain terminators prescribed indefinitely such as zidovudine. With a daily dose of 500 mg zidovudine a person receives 2 x 10 to power 20 molecules, or 2 x10 to power 6 for every human cell, every day for the rest of his life. By contrast, after 11 years of research the HIV hypothesis has yet to identify a single molecule that could be pathogenic.[xiii] In view of this and the complete failure of the HIV hypothesis to produce public health benefits, non-HIV hypotheses must be studied more carefully.

Department of Molecular and Cell Biology
University of California
Berkeley
California 94720-3206
USA
Peter Duesberg professor


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without HlV. Genetica 1995;95:51-70.

ia. Duesberg P. Is HlV the cause of AlDS? Lancet 1955;346:1371-2.

ii. Sabin CA, Pasi KJ, Phillips AN, Lilley P, Bofill M, Lee CA. Comparison of
immunodeficiency and AIDS defining conditions in HIV negative and HlV positive
men with haemophilia A. BMJ 1996;312:207-10.

iii. Centers for Disease Control and Prevention. US HIV and AIDS cases repotted
through December 1994. HIV/AIDS Surveillance Report 1994;6:1-39.

iv. Ho D. Quantification of human immunodeficiency virus m the blood. N Engl J
Med 1990;322:1467.

v. Kreiss JK, Kasper CK, Fahey JL, Weaver M, Visscher BR, Stewart JA, et al 
Nontransmission of T-cell subset abnormalities from hemophiliacs to their
spouses. JAMA 1984;251:1450-4.

vi. Chorba TL, Holman RC, Strine TW, Clarke MJ, Evatt BL. Changes in longevity
and causes of death among persons with hemophilia A. Am J Hematol 1994;45:112-21.

vii. Darby SC, Ewart DW, Giangrande PLF, Dolin PJ, Spooner RJD, Rizza CR, et al.
Mortality before and after HIV infection in the complete UK population of
haemophiliacs. Nature 1995;377:79-82.

viii. Retrovir. In: Physicians' desk reference Orandell, New Jersey: Medical
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ix. Goedert JJ, Cohen AR, Kessler CM, Eichinger S, Seremetis SV, Rabkin CS, et
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concentrate. Lancet 1994;344:791-2.

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xi. De Biasi R, Rocino A, Miraglia E, Mastrullo L, Quirino AA. The impact of a
very high purity of factor Vlll concentrate on the immune system of human
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comparison with an intermediate purity concentrate. Blood 1991 ;78:1919-22.

xii. Seremetis SV, Aledort LM, Bergman G, Bona R, Bray G, Brettler D, et al.
Three-year randomised study of high-purity or intermediate-purity factor Vlll
concentrates in symptom-free HlV-seropositive haemophiliacs: effects on immune
status. Lancet 1993;342:700-3.

xiii. Cohen J. Researchers air alternative views on how HIV kills cells. Science
1995;269:1044-5.

Response: Arguments contradict the "foreign protein-zidovudine" hypothesis

Caroline A Sabin, Andrew N Phillips, Christine A Lee

In 1991 Duesberg challenged researchers to provide either data on "controlled epidemiologic studies comparing matched hemophiliacs,- with and without HIV, or epidemiological evidence that the mortality of hemophiliacs is increased by HIV."[i] We and Darby et al have provided that evidence.[ii,iii] Duesberg's commentary [iv] requires further comment.

HIV may be enough to cause AIDS

It is incorrect to conclude that HIV is not sufficient to cause AIDS simply because some of the infected patients in our study had not developed AIDS by 10 years after seroconversion. Only longer term follow up studies will finally establish whether all HIV positive patients would, given enough time, ultimately develop AIDS. In the United States around 3,800 haemophilic patients have reportedly developed AIDS out of 9,000 who have been infected[v] (World Federation of Hemophilia, personal communication, 1995), a far higher proportion than that quoted by Duesberg in arguments against the HIV hypothesis.

Duesberg's foreign protein-zidovudine hypothesis predicts that haemophilic patients will not develop non-immunodeficiency diseases such as dementia. Given the low prevalence of some of the 26 different AIDS defining conditions it would not be expected that we should witness all conditions among our 17 patients. However, dementia is well documented in HIV positive haemophilic patients and occurs with a similar prevalence to that in other exposure categories (Xen Santas, Centers for Disease Control, personal communication, 1995). Among all 111 HIV positive haemophilic patients at this hospital, dementia occurred in six.

Duesberg points out that lifetime usage of concentrate may be expected to be different between a 60 year old and a 14 year old (our pair 3). Unfortunately, lifetime usage of concentrate was not available in these patients and therefore usage patterns over 10 years were used. However, it is important to remember that clotting factor concentrate was introduced in our centre in 1978 on average, so that age differences in the pairs may suggest larger differences in lifetime usage than actually existed. Even when the analysis was restricted to pairs in whom the HIV positive patient was younger than or the same age as the HIV negative patient (eight pairs) the results remained similar: four of eight HIV positive patients developed AIDS defining diseases compared with none of the eight HIV negative patients. Furthermore, since 1980 none of 400 HIV negative haemophilic patients registered at this hospital has developed AIDS despite having received clotting factor concentrates on average since 1978, and CD4 counts in these patients have been similar to those of HIV negative heterosexual subjects.[vi]

Contrary to Duesberg's assertion, sexual transmission of AIDS has been observed at our centre. At the Royal Free Hospital sexual transmission of HIV to partners with no other risk factors for HIV has occurred in three cases. Of these infected partners, one developed AIDS and died (the haemophilic partner of this patient also died with AIDS), one was symptomatic with a CD4 count of zero but remained AIDS free, and the third remained asymptomatic but with a CD4 count of 0.2 x 10 to power 9/l. No wives of any other haemophilic patients at our centre have developed AIDS.

Patients are given zidovudine because they are ill

It is not true that most British haemophilic patients infected with HIV have been given zidovudine since 1987. Initially patients were given zidovudine after the development of AIDS. Subsequently, since around 1989, patients have been given zidovudine once their CD4 count has fallen below 0.2 x 10 to power 9/l or after the development of symptomatic disease. Similar recommendations are made for pentamidine or co-trimoxazole as prophylaxis against Pneumocystis carinii pneumonia. Consequently, by the time patients begin zidovudine and pentamidine they have low CD4 cell counts and are usually symptomatic.

Observational studies often show that patients given zidovudine have a worse prognosis than untreated patients.' Patients receiving zidovudine are selectively treated because they are ill. The interpretation of findings from these studies should not therefore be that zidovudine increases the risk of AIDS. Of the nine patients developing AIDS in our study, seven received zidovudine only after an initial AIDS diagnosis when immunological deterioration had already occurred. There is no possibility, therefore, that either zidovudine or pentamidine had a causal role in the initial development of symptomatic disease in these patients.

Finally, though there may be some beneficial effect of high purity clotting factor concentrates on the immune systems of patients with haemophilia,[viii] there is little evidence that this has translated into clinical benefit for these patients.[vii] Conversely, a recent paper has suggested that increased usage of intermediate purity clotting factor concentrates may be beneficial for HIV positive haemophilic patients.[ix]

Despite the provision of new data which support the HIV hypothesis for the development of AIDS, the arguments proposed by Duesberg in his commentary remain unchanged and contradict the "foreign protein-zidovudine" hypothesis. For the benefit of patients infected with HIV it must now be time to move on to enable researchers to devote time to the real issues at hand.

HIV Research Unit
Department of Public Health
Royal Free Hospital School of Medicine
London NW3 2PF
Caroline A Sabin lecturer in epidemiology and medical statistics
Andrew N Phillips reader in epidemiology and biostatistics

Haemophilia Centre and Haemostasis Unit
Department of Haematology
Royal Free Hospital and School of Medicine
London NW3 2PF
Christine A Lee director haemophilia centre

Correspondence to: Dr Sabin.

i. Duesberg PH. AIDS epidemiology: inconsistencies with human immunodeficiency
virus and with infectious disease. Prac Natl Acad Sci 1991;88:1575-9.

ii. Sabin CA, Pasi KJ, Phillips AN, Lilley P, Bofill M, Lee CA. Comparison of
immunodeficiency and AIDS defining conditions in HIV negative and HlV positive
men with haemophilia A. BMJ 1996;312:207-10

iii. Darby SC, Ewart DW, Giangrande PLF, Dolin PJ, Spooner RJD, Rizza CR, et al.
Mortality before and after HIV infection in the complete UK population of
haemophiliacs. Nature 1995;377:79-82.

iv. Duesberg P. Commentary: non-HlV hypotheses must be studied more carefully.
BMJ 1996;312:000-00.

v. Centers for Disease Control and Prevention. US HIV and AIDS cases repotted
through December 1994. HIV/AIDS Surveillance Report 1994;6:1-39.

vi. Bofill M, Janossy G, Lee CA, MacDonald-Burns D, Phillips AN, Sabin C, et al.
Laboratory control values for CD4 and CD8 T Iymphocytes. Implications for HlV-I
diagnosis. Clin Exp Immunol 1992;88:243-52.

vii. Goedert JJ, Cohen AR, Kessler CM, Eichinger S, Seremetis SV, Rabkin CS, et
al. Risks of immunodeficiency, AIDS and death related to purity of factor Vlll
concentrate. Lancet 1994;344:791-2.

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Magnitude of benefit from earlier thrombolytic treatment in acute myocardial infarction: new evidence from Grampian region early anistreplase trial (GREAT)

John Rawles

Abstract

Objective - To generalise from the results of the Grampian region early anistreplase trial (GREAT) and to express the benefit of earlier thrombolysis in terms of lives saved per hour of earlier treatment.

Design - Multivariate analysis of a randomised double blind trial.

Setting - 29 rural practices in Grampian region and teaching hospitals in Aberdeen.

Subjects - 311 patients with suspected acute myocardial infarction and without contraindications to thrombolysis who were seen by their general practitioners within four hours of the start of symptoms.

Interventions - Anistreplase 30 units given intravenously, either by general practitioners before hospitalisation or later in hospital.

Main outcome measure - Death within 30 months of entry into trial.

Results - Death within 30 months was positively related to age (P less than 0.0001) and to delay between start of symptoms and thrombolytic treatment (P equals 0.0004). However, the probability of dying rose exponentially with earlier presentation, so death within 30 months was negatively related to the logarithm of the time of randomisation (P equals 0.0163). In patients presenting two hours after start of symptoms each hour's delay in receiving thrombolysis led to the loss of 21 lives per 1,000 within 30 days (95% confidence interval 1 to 94 lives per 1,000) (P equals 0.03) and 69 lives per 1000 within 30 months (16 to 141 lives per 1,000) (P equals 0.0004).

Conclusions - The magnitude of the benefit from earlier thrombolysis is such that giving thrombolytic treatment to patients with acute myocardial infarction should be accorded the same degree of urgency as the treatment of cardiac arrest.

Medicines Assessment Research Unit
University of Aberdeen
Aberdeen AB9 2ZD
John Rawles honorary senior lecturer

Outlook for survivors of childhood in sub-Saharan Africa: adult mortality in Tanzania

Henry M Kitange, Harun Machibya, Jim Black, Deo M Mtasiwa, Gabriel Masuki, David Whiting, Nigel Unwin, Candida Moshiro, Peter M Klima, Mary Lewanga, KGMM Alberti, Donald G McLarty on behalf of the Adult Morbidity and Mortality Project

Abstract

Objective - To measure age and sex specific mortality in adults (15-59 years) in one urban and two rural areas of Tanzania.

Design - Reporting of all deaths occurring between 1 June 1992 and 31 May 1995.

Setting - Eight branches in Dar es Salaam (Tanzania's largest city), 59 villages in Morogoro rural district (a poor rural area), and 47 villages in Hai district (a more prosperous rural areas;

Subjects - 40.304 adults in Dar es Salaam, 69964 in Hai, 50 465 in Morogoro rural.

Main outcome measures - Mortality and probability of death between 15 and 59 years of age (45-Q-15)

Results - During the three year observation period a total of 4,929 deaths were recorded in adults aged 15-59 years in all areas. Crude mortalities ranged from 6.1/1,000/year for women in Hai to 15.9/1,000/year for men in Morogoro rural. Age specific mortalities were up to 43 times higher than rates in England and Wales. Rates were higher in men at all ages in the two rural areas except in the age group 25 to 29 years in Hai and 20 to 34 years in Morogoro rural. In Dar es Salaam rates in men were higher only in the 40 to 59 year age group. The probability of death before age 60 of a 15 year old man (45-Q-15) was 47% in Dar es Salaam, 37% in Hai, and 58% in Morogoro; for women these figures were 45%, 26%, and 48% respectively. (The average 45-Q-15s for men and women in established market economies are 15% and 7%, respectively.)

Conclusion - Survivors of childhood in Tanzania continue to show high rates -of mortality throughout adult life. As the health of adults is essential for the wellbeing of young and old there is an urgent need to develop policies that deal with the causes of adult mortality.

Ministry of Health
PO Box 9083
Dar es Salaam
Tanzania
Henry M Kitange specialist physician
Deo M Mtasiwa district medical officer
Gabriel Masuki district medical officer
Harun Machibya district medical officer
Mary Lewanga field supervisor

c/o Redd Bama
PO Box 4581
Harare
Zimbabwe
Jim Black public health specialist

Department of Medicine
Medical School
University of Newcastle upon Tyne
Newcastle upon Tyne NE2 4HH
David Whiting data manager
KGMM Alberti professor of medicine
Donald G McLarty professor of medicine

Departments of Medicine and Epidemiology and Public Health
Medical School
University of Newcastle upon Tyne
Newcastle upon Tyne NE2 4HH
Nigel Unwin Barclay lecturer in epidemiology

Muhimbili Medical Centre
PO Box 65001
Dar es Salaam
Tanzania
Candida Moshiro statistician

Dar es Salaam Urban Health Project
PO Box 63320
Dar es Salaam
Tanzania
Peter M Kilima director of preventive services

Correspondence to: Professor D G McLarty, Muhimbili Medical Centre, PO Box 63320, Dar es Salaam, Tanzania.

Management of labour in an isolated rural maternity hospital

A G Baird, D Jewell, J J Walker

Abstract

Objectives - To evaluate the use of a maternity unit run by general practitioners and midwives, describing the outcome of labour in an unselected group of women and quantifying the contribution made by general practitioners.

Design - Retrospective population based review of obstetric patients who had access to an isolated rural maternity unit.

Setting - Rural area 120 km from a consultant maternity unit.

Subjects - 997 consecutive women delivered between January 1987 and May 1991.

Main outcome measures - Mode of delivery and complications by place of booking and place of delivery; need for medical intervention and transfer.

Results - 530 women (53%) were booked for delivery in the rural unit; this group had a caesarean section rate of 3.8% and an unplanned transfer rate of 12.8% to the consultant unit in labour. Of the 462 who delivered in the low risk unit, 25 (5%) required a forceps delivery; postnatal complications requiring emergency medical support occurred in a further 33 (7%)

Conclusions - Risk characterisation is possible, but medical support from general practitioners and obstetricians is required in almost a third of women at low risk for complications of delivery. Results of this study support the team approach to obstetric management but not the move towards isolated units without organised medical support.

The White House
Sandhead
Stranraer
Wigtownshire DG9 9JA
A G Baird general practitioner

Department of Social Medicine
University of Bristol
Bristol BS8 2PR
D Jewell senior lecturer

University Department of Obstetrics and Gynaecology
St James's University Hospital
Leeds LS9 7TS
J J Walker professor in obstetrics and gynaecology

Correspondence to: Dr Baird.