Follow up after a family based genetic screening programme for familial hypercholesterolaemia: is screening alone enough?BMJ 2002; 324 doi: https://doi.org/10.1136/bmj.324.7350.1367 (Published 08 June 2002) Cite this as: BMJ 2002;324:1367
- Merel C van Maarle, physiciana (, )
- Marlies E A Stouthard, psychologista,
- Perla J Marang-van de Mheen, health scientistb,
- Niek S Klazinga, professor in social medicinea,
- Gouke J Bonsel, professor in public health methodsa
- a Department of Social Medicine, Academic Medical Centre, University of Amsterdam, PO Box 22700, 1100 DE Amsterdam, Netherlands
- b Department of Medical Decision Making, Leiden University Medical Centre, PO Box 9600, 2300 RC Leiden, Netherlands
- Correspondence to: M C van Maarle
Familial hypercholesterolaemia is an autosomal dominant disorder of lipoprotein metabolism, with an estimated frequency of 1 in 500 in Western countries; it results in excess mortality from coronary artery disease.1 Now that the genetic defects can be detected and statins are available to lower lipids effectively, genetic screening has been considered.2–3 In 1994 a family based genetic screening programme for familial hypercholesterolaemia started in the Netherlands. The programme's effectiveness rests on the evidence based treatment of newly identified patients. We therefore assessed the subsequent preventive care and short term clinical outcome in people testing positive for familial hypercholesterolaemia as a proxy for the expected long term level of coronary artery disease.4
Participants, methods, and results
The foundation for tracing hereditary hypercholesterolaemia performs cascade screening in families of patients with clinically diagnosed familial hypercholesterolaemia with a known mutation, actively approaching first degree and second degree relatives.5 Family members are tested for the known mutation; their cholesterol level is not measured. The test result is communicated only to the person screened (by mail). The foundation is not involved in subsequent treatment or in monitoring follow up.
We conducted the evaluation study from March to September 1998 in all 215 people who tested positive from a consecutive cohort of 677 people screened as part of the programme. The inclusion criteria were consent to genetic testing and the current study, a positive test result, and age 18 or over.
We collected data with three self administered questionnaires—at screening and at 7 months and 18 months after communication of the test result. The main outcome measures were quality of treatment according to the key recommendations of the Dutch guidelines on hypercholesterolaemia and quality of clinical outcome by achieved cholesterol level, body mass index, and smoking status (table).4
We divided the people testing positive into two categories: those with an unknown cholesterol concentration or with normal cholesterol without treatment at the time of screening (“newly identified cases”) and those known to have hypercholesterolaemia (cholesterol ≥6.5 mmol/l) or being treated for this condition (“confirmed cases”).
One hundred and sixty six (77%) participants filled out all three questionnaires. Respondents and people lost to follow up differed in only one characteristic—use of statin (57% v 39%, P<0.05).
Seventy three (44%) respondents were men, 41 (25%) were newly identified, and 125 (75%) were confirmed cases. The confirmed cases were older (48.2 v 38.9 years), had higher cholesterol concentrations (10.7 v 6.0 mmol/l), if known, and were more likely to have at least one first degree relative with cardiovascular disease (62 (50%) v 13 (32%)) or one premature cardiovascular death in the family (26 (21%) v 2 (5%)) (P<0.05 for all comparisons).
Although the quality of treatment and clinical outcome improved substantially over time in both groups (table), people testing positive for familial hypercholesterolaemia did not attain an optimal level of care. Quality of treatment was still unsatisfactory in 33 (20%) cases, and quality of clinical outcome was still insufficient in 75 (45%). Fifty eight (35%) participants were hypercholesterolaemic at follow up, nine (16%) of those with hypercholesterolaemia did not take statins, and 40 (24%) participants smoked.
Both confirmed and newly identified patients benefit from screening for familial hypercholesterolaemia, as their risk status improves and cholesterol lowering treatment is instituted, but in almost half of all cases the achieved level of care does not keep up with current guidelines. Opportunities for improvement towards current guidelines include physician education, better implementation of guidelines, and, especially, an intensification of the link between diagnosis and follow up care in the screening process.
We thank the respondents for their enthusiasm and Marina Umans-Eckenhausen and the genetic field workers of the foundation for tracing hereditary hypercholesterolaemia for their support and help with inclusion of the study population.
Contributors: All authors conceived the study, and MCvM and MEAS collected the data. MCvM, MEAS, and GJB contributed to the analysis and interpretation of the data, and all authors contributed to the preparation of the paper. MCvM is the guarantor.
Funding Health Research and Development Council of the Netherlands (grant number 28-2751).
Competing interests None declared.