Follow-up of the WHO multinational study of vascular disease in diabetes: general description and morbidity

Aims. The incidence of retinal, renal and cardiovascular complications and their relation to baseline risk factors was documented in this follow-up st udy of 10 of the 14 original centres of the WHO Multinational Study of Vasc ular Disease in Diabetes (WHO MSVDD). Methods. The incidence of specified items of vascular disease and some asso ciated risk factors was ascertained after 7 to 9 years (11-12 years in Okla homa, USA) follow-up, re-using baseline examination methodology in 3165 pat ients (66.9%) and, through secondary information in 717 (15.2%) of the 4729 original patients, of whom 540 (11.4%) had died and 307 (6.5%) were untrac eable. Results. During follow-up, approximately one third of the patients develope d hypertension and one third started insulin. Coronary heart disease incide nce varied 10 to 20-fold among centres as did limb amputation rates. Inter- centre differences in incident retinopathy and severe visual impairment wer e smaller but incident clinical proteinuria and renal failure varied marked ly. Vascular disease incidence of all categories was high in Native America ns though coronary heart disease incidence was relatively low in Pima India ns and absolutely low in Hong Kong and Tokyo patients. Specific vascular ev ents and their relation with baseline risk factors are analysed in accompan ying papers, summarised in the Epilogue. Conclusion/interpretation. These 10 centres reported very different inciden ce rates of vascular complications. Observer variation, selection biases an d competing causes of mortality contributed to these differences but their validity is supported by the more objective outcome indicators. The followi ng papers also suggest that baseline factors such as raised arterial pressu re, cholesterol and fasting glucose (in the centres where it was measured) were important and potentially reversible predictors of risk.