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Incidence and remission rates of lower urinary tract symptoms at one year in women aged 40-60
- Simon Jackson (5 June 2000)
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Reply to Jackson et al
- Lars Alling Møller (8 June 2000)
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Practical implications
- Francis Lam (11 July 2000)
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Incidence & remission rates of lower uri nary tract symptoms
- C W McGrother (17 July 2000)
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Simon Jackson
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Moller et al are to be congratulated on their longitudinal study of female lower urinary tract symptoms. The questionnaire used was not described in detail but appears to be based upon 2 different instruments (1,2). The Bristol Female Lower Urinary Tract Symptoms (B-FLUTS) questionnaire (2) uses a 5 point scale for reporting symptoms, respondents have the option of replying "never", "occasionally", "sometimes", "most of the time" or "all of the time" to a particular symptom, and when asked about frequency they can reply "never", "once or less per week", "2-3 times per week", "once per day" or "several times per day". This raises the issue of reproducibility when the questionnaire is completed on more than one occasion. Reproducibility of our instrument was good when a test- retest analysis was performed at a two week interval, there being no apparent change in the underlying condition during that time; 78% of symptom questions were answered identically on both occasions, with no responses changing by more than 2 categories. The instrument used by Moller is reported to have "fair to excellent" reproducibility but details are not supplied. The definition used in their paper for incidence was "the proportion of women in whom symptoms arise, or increase from sometimes to weekly or more". Remission is defined as "the proportion of women with symptoms occurring weekly or more in whom symptoms decreased to less than weekly". It would appear therefore that a change in questionnaire response by one category could be recorded as incidence or remission. If reproducibility is similar to the B-FLUTS questionnaire over 20% of women, in whom there has been no apparent change in their underlying condition, will change their response by 1 category or more over a two week period. Standardised questionnaires that have been tested for validity and reliability should be used whenever possible so that these sorts of measurement errors can be calculated. Moller may simply be confirming test-retest error and the conclusion that there is an incidence and remission rate of 10.0% and 27.8% for female lower urinary tract symptoms over the course of one year should be interpreted with caution. 1 Bernstein I, Sejr T, Able I, Andersen JT, Fischer-Rasmussen W, Klarskov P, et al. Assessment of lower urinary tract symptoms in women by a self-administered questionnaire: test-retest reliability Int Urogynecol J Pelvic Floor Dysfunction 1996;7:37-47 2 Jackson S, Donovan J, Brookes S, Eckford S, Swithinbank L, Abrams P. The Bristol female lower urinary tract symptoms questionnaire: development and psychometric testing. Br J Urol 1996; 77: 805-12. Simon Jackson.
Jenny Donovan
Paul Abrams
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Lars Alling Møller, MD,Phd Dept.gyn.obs. County Hosp, Glostrup, DK
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Jackson, Donovan and Abrams enquire about the reliability of our study. The problem is: are reported changes in LUTS real or a methodological artefact because of poor reproducibility? This is a very relevant and an important topic. We apologise that it is difficult to find all relevant data in the published paper to fully assess this problem. We are therefore pleased hereby to be able to elaborate further on our data. Our questionnaire was based on The Bristol Female Lower Urinary Tract Symptoms as mentioned. However, the number of answering categories was shortened as to "never", "sometimes", "weekly or more (often)" or "daily or more (each time)". In our experience a more detailed division only tends to weaken reproducibility. To test reproducibility we asked a subgroup of 100 women from the study to fill in identical questionnaires two weeks apart. The subgroup comprised 50 women reporting one or more LUTS and 50 women reporting no LUTS. Otherwise selection was randomised. Response rate was 77%. In terms of calculating reproducibility data were divided into two groups comprising women with symptoms more than or equal to symptoms weekly (often) and women with less/no symptoms, respectively. Classification into these groups was not arbitrary but thought to be a clinical relevant cut off line as the line as well separated women with from women with out bothersomeness (1). Regarding urinary incontinence the test-retest showed an agreement in women with symptoms more than or equal to symptoms weekly (often) on 86.4%, in women with less/no symptoms on 94.5%; overall 92.2%. Regarding LUTS calculated agreements were 93.1% and 97.9%, respectively; overall 96.1%. In comparison Jackson et al found that 78% of symptom questions were answered identically on both occasion (2). We assume this number is an overall estimate? It is, however, well known that reproducibility associates with the prevalence of a specific disease. If the prevalence is low (as it usually is) overall reproducibility is misleading and one should consider using kappa. At least one should specifically report reproducibility in the symptom group as well as in the asymptomatic group. Moreover, by using an overall estimate Jackson et al in their study indirectly assume an underlying continuos scale, that the distance from one category to another is equal regardless types of category. As previously mentioned: we believe this is not the case as we observed a sharp increment in bothersomennes when moving from women with symptoms sometimes to women with symptoms weekly (often) (1). In conclusion we believe that the instrument we have used is capable to measure incidence and remission rates of urinary incontinence and LUTS. However, we agree with the Bristol group that our estimated rates should be interpreted with caution, as some fluctuation inevitably are part of a questionnaire design. Thus the true incidence and remission rate could be lower than reported. 1. Møller LA, Lose G, Jørgensen T. The prevalence and bothersomeness of lower urinary tract symptoms in women 40-60 years of age. Acta Obstet Gynecol Scand 2000; 79: 298-305. 2. Jackson S, Donovan J, Brookes S, Eckford S, Swithinbank L, Abrams P. The Bristol female lower urinary tract symptoms questionnaire: development and psychometric testing. Br J Urol 1996; 77: 805-812 Lars Alling Møller, Gunnar Lose, Department of Obstetrics and Gynaecology, Glostrup County Hospital, University of Copenhagen, DK-2600 Glostrup, Denmark. |
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Francis Lam
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Dear Editor - We read with interest the study by Moller et al [1] who found that the remission rate of lower urinary tract symptoms was as high as 27.8% and that no single treatment modality including antibiotic therapy was found to be beneficial on these symptoms overall. This has important practical implications, especially for those who see patients with this disorder regularly in the primary care setting. In our hospital, we have conducted a study examining the extent of non- compliance in patients prescribed with antibiotics in the Accident and Emergency department and found that 31% of patients admitted to taking none or substantially less than the full course of antibiotics.[2] Given the fact that a quarter of women with lower urinary tract symptoms remit in one year with or without treatment and that on average one out of three patients will not be compliant with the antibiotic therapy, it seems rational therefore to limit the use of empirical antibiotics especially in those with equivocal evidence of infection. Perhaps more emphasis should be placed on communication with the patient together with appropriate advice and reassurance, for example information leaflets. Moreover, when treatment is indicated, we would advocate a short course (three days) of antibiotics which has been shown to be as effective as a seven [3] or ten [4] day therapy. This is in line with the recommendation by the SMAC Report striving to reduce the selection pressure for antibiotic resistance.[5] References: [1] Moller LA, Lose G, Jorgenson T. Incidence and remission rates of lower urinary tract symptoms at one year in women aged 40-60: longitudinal study. BMJ 2000; 320: 1429-32. [2] F. Lam, F. Stevenson, N. Britten, I. Stell. Compliance to antibiotics prescribed in Accident and Emergency : the influence of consultation factors. The Journal of Accident and Emergency Medicine. 2000; 17: 71. [3] Trienekens TAM, Stobberingh EE, Winkens RAG, Houben AW. Different lengths of treatment with co-trimoxazole for acute uncomplicated urinary tract infections in women. British Medical Journal 1989; 299: 1319-1322. [4] Charlton CAC, Crowther A, Davies JG, Dynes J, Haward MWA, Mann PG, Rye S. Three day and ten day chemotherapy for urinary tract infections in general practice. British Medical Journal 1976; 1:124-126. [5] Standing Medical Advisory Committee Sub-Group on Antimicrobial Resistance 'The path of least resistance' published by The Department of Health. 1997 Mr Francis Lam MRCS(Ed) ( Senior House Officer ),
Correspondence to Mr F.Lam, 4 Middlefield, London NW8 6NE |
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C W McGrother
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Dear Sir - We read with interest the article by Moller et al1. Although a well conducted study, it was disappointing to find that the analysis and interpretation were poorly developed, making it potentially misleading to some readers and difficult to appreciate the full value of such prospective studies. Incidence tells us the rate of development of new cases within a continent population, whilst remission tells us the rate of recovery within an incontinent population. Clearly these two rates cannot be directly compared. If the actual number of new cases and remissions had been shown in Table 2, they would probably have conveyed a fairly steady state of prevalence which is actually the case. The authors claim their incidence rate (5.8%) is comparable with other studies (2-2.5%) but we have seen incidence rates of 1-22%2,3,4. Similarly, they compare their remission rate of 38% with other studies (3- 13%) but we have found remission rates varying between 6 and 26%4,5. Undoubtedly differences in definition are important, but what is especially different in this study is the age range 40-60 compared to 65 and over in previous studies. It is quite plausible that younger cohorts have relatively low incidence and high remission rates. It is also relevant that all the studies are small scale and subject to substantial variation due to chance. The association between remission and certain factors is also explored in this paper and it is suggested that symptoms improved as a consequence of medical awareness or drug treatment. No consideration is given to the likely connection with other, possibly transient, morbidity and the natural tendency to heal which could render contact with services confounding rather than causal. Finally, the overall interpretation of the added value of this study is especially vague. It would have been appropriate for example, to point out that an incidence rate is a guide to the number of new cases needing assessment in a population each year in comparison with other conditions. Remission rates are useful reference points for interpreting the magnitude of an effect of treatment in uncontrolled trials. Together these rates allow a deeper understanding of the behaviour of the problem and its prognosis. Dr C.W. McGrother, Senior Lecturer in Epidemiology Dr H. Dallosso, Research Associate Mrs M. Donaldson, Research Associate and the MRC Incontinence Study Team Department of Epidemiology and Public Health, University of Leicester, 22-28 Princess Road West, Leicester, LE1 6TP References 1. Moller et al. Incidence and remission rates of lower urinary tract symptoms at one year in women aged 40-60: a longitudinal study. BMJ 27 May 2000; 320: 1429-1432. 2. Holtedahl K, Hunskaar S. Prevalence, 1-year incidence and factors associated with urinary incontinence: a population based study of women 50-74 years of age in primary care. Maturitas Journal of the Climacteric and Postmenopause 1998; 28:205-211. 3. Burgio KL, Matthews KA, and Engel BT. Prevalence, incidence and correlates of urinary incontinence in healthy, middle-aged women. J. Urol 1991; 146:1255-1259. 4. Herzog AR, Diokno AC, Brown MB, Normolle DP, Brock BM. Two year incidence, remission and change patterns of urinary incontinence in non-institutionalised older adults. J Gerontol 1990; 45: M67-M74. 5. Nygaard IE and Lemke JH. Urinary incontinence in rural older women: prevalence, incidence and remission. J Am Geriat Soc 1996;44:1049- 1054. |
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