Durability of improvement achieved in a clinical trial - Is compliance an issue?

BACKGROUND The effects seen in clinical trials may not translate to actual practice situations. We examined the persistence of blood pressure effects 31 months after a clinical trial of treatment with hypotensive agents. METHODS Nineteen previously untreated middle-aged men with hypertension had their office and ambulatory blood pressure recorded after 4 weeks of place bo treatment, 4 weeks of active treatment in a clinical trial, and 31 month s of treatment in clinical practice. All recording was clone by the same ph ysician (IE). RESULTS Mean 24-hour blood pressure was 138/92 mm Hg after 4 weeks of place bo treat ment, 128/85 mm Hg after 4 weeks of active treatment in the clinic al trial, and 136/87 mm Hg after a mean of 31 months of treatment in clinic al practice. The corresponding blood pressure values greater than or equal to 140/90 mm Hg during the daytime were 47%, 24%, and 39%. and office blood pressures were 155/101, 145/93, and 150/91 mm Hg. individual comparison re vealed that 6 of the 19 patients had higher mean 24-hour blood pressure aft er several months of treatment in clinical practice than after several week s of active treatment in the clinical trial. CONCLUSIONS In our study, the significantly reduced blood pressure in the c linical trial did not persist when followed up in clinical practice. At fol low-up, one third of the patients had blood pressure values similar to thos e before active treatment. The reason for this is unclear, but inconsistent compliance may play a part in the lack of durability, of the improvements. Our results indicate that effects seen in short-term clinical trials may n or translate lo long-term benefits in clinical practice.