Discontinuation and switching of therapy after initiation of lipid-lowering drugs: the effects of comorbidities and patient characteristics.

To evaluate the effects of comorbidities and patient characteristics on treatment continuation among patients starting their first course of lipid-lowering drug (LLD) therapy. Within the UK General Practice Research Database (GPRD), we identified 22 408 patients who started LLD therapy due to coronary heart disease, hyperlipidaemia, or other atherosclerotic diseases, and who received > or = two prescriptions for LLD between January 1 1990 and December 31 1997. Differences in potential predictors of treatment continuation between patients who continued, and patients who discontinued/switched lipid-lowering therapy within 1 year after treatment initiation were compared by fitting multivariate logistic regression models. The effects of baseline characteristics on treatment continuation after switching of LLDs were also analysed. Discontinuation/switching of lipid-lowering therapy was common during the study period, especially among patients who received nonstatin, nonfibrate LLDs (log-rank test P = 0.0001). Statin use, more frequent physician visits, more concurrent cardiovascular medications, diabetes, and fewer noncardiovascular medications were associated with treatment continuation of LLDs. Among patients who switched therapy, prescribing of a statin as the substituted LLD, more concurrent cardiovascular medications, and later treatment switching were related to a higher probability of treatment continuation after switching LLDs. Treatment continuation after initiation or switching of lipid-lowering therapy largely increased with concomitant cardiovascular comorbidities, and more health care utilization, and is more common for statins than for other LLDs. Practice guidelines, patient education, and quality of care assessment for lipid-lowering therapy should emphasize factors that predispose patients to discontinuation/switching, in an effort to optimize the choice of therapeutic regimens and to improve patient adherence.