The impact of thiazide diuretics on the initiation of lipid-reducing agents in older people: a population-based analysis.

Abstract

OBJECTIVE: The objective of this study was to examine how often treatment for hyperlipidemia followed the use of thiazides, compared with the use of other antihypertensive drugs, in older patients. DESIGN: Retrospective follow-up of all health claims filed over a 12-month period. SETTING: New Jersey Medicaid and Medicare programs. PARTICIPANTS: A total of 9274 enrollees, aged 65 to 99, who were newly initiated on antihypertensive medications from 1981-1989. MEASUREMENTS: We measured rates of lipid-reducing agent (LRA) initiation among patients in the 2 years following antihypertensive initiation (thiazide, non-thiazide drug, or combinations of the two) compared with rates among patients not currently taking antihypertensive agents. We used Cox regression analyses to estimate relative risks (RR), accounting for switching in antihypertensive therapy and for time when drug therapy was not currently available according to pharmacy refill records. RESULTS: There were 226 patients (2.4%) in the cohort who were started on LRA during the follow-up period. After adjusting for potential confounders, we found no significant relationship between LRA initiation and overall thiazide use (RR 1.47, 95% CI 0.89-2.40), or other antihypertensive use, relative to no current exposure. However, use of high-dose thiazides (> or = 50 mg) was associated significantly with LRA initiation (RR 1.97, 95% CI 1.12-3.45). Factors associated with decreased incidence of LRA use included age > or = 85 (RR 0.59, 95% CI 0.36-0.96), black race (RR 0.58, 95% CI 0.37-0.91), and nursing home residency (RR 0.20, 95% CI 0.11-0.35). CONCLUSION: Use of low-cost and effective thiazide diuretics in older hypertensives was not associated with more common initiation of lipid-reducing agents, except with high-dose use of thiazides currently seen as inappropriate in most cases. Age and race were important determinants of LRA use.