Physicians' prescribing attitudes to combined therapy with statins and fibrates

To assess the impact of a package insert revision and a drug-drug interaction warning embedded in a computerized prescription ordering system, on physicians' prescribing of concomitant statins and fibrates.

Data were obtained using a computerized prescription order entry system before and after administrative intervention advising of potentially adverse effects of this combined therapy. The number of prescriptions for statins and fibrates were counted monthly from January 1998 to June 2002 at the National Cardiovascular Center (NCVC). Counting was based on information from a prescription database file compiled from a computerized order entry system. The total number of prescriptions and frequency of requests for statins and fibrates were compared with the timing of either package insert revision or introduction of the warning on a computerized prescription ordering system. In addition, laboratory testing of renal function using serum creatinine (Scr) assays in patients treated with combined statins and fibrates was obtained from medical records at two stages during the study period (stage 1, January 1998 to June 1998; stage 2, January 2002 to June 2002).

There were 204 prescriptions for concomitant statins and fibrates at the beginning and 50 prescriptions at end of the study period. The number of prescriptions began to decrease in the latter half of 1999 with the percentage of concomitant use of statins and fibrates showing an evident downward trend from January 2001. This acceleration in the downward trend coincided with the introduction of the computerized warning message. Scr levels were measured in 43.8% of patients in stage 1 and in 48.3% of patients in stage 2 in the past month. The percentage of patients having Scr levels measured in the past 6 months was 85.3% in stage 1 and 84.5% in stage 2. There was no significant difference in the percentages of patients whose Scr levels had been measured between the two stages.

Revision of package inserts concerning combined therapy of statins and fibrates led to physicians' prescribing fewer of these combinations. A warning message displayed on a computerized prescription order entry system accentuated this effect.