Antibiotics are among the most commonly used classes of agents in community practice; yet, studies of antibiotic use in this setting are scarce. Data from developed countries suggest increasing use of newer broad-spectrum agents, which has implications for the development of antibiotic resistance as well as cost of therapy. In this study, we quantified changing patterns of antibiotic use in community practice in Manitoba, Canada, from 1995 to 1998.
A descriptive, population-based study of antibiotic use in Manitoba was facilitated by the Drug Programs Information Network (DPIN) of Manitoba Health; a data management system responsible for recording details of prescriptions dispensed for all Manitoba residents. Antibiotic use data, defined as numbers of prescriptions dispensed, were extracted from the DPIN from January 1, 1995, to March 31, 1998. Antibiotic use is reported as prescriptions per 1000 persons per year (Rx/1000/Yr) based on quarterly use.
Penicillins (48.3%), macrolides (16.0%), and sulfonamides (12.5%) accounted for 75% of total antibiotic use; total use decreased 19.1% between 1995 and 1998. Use of the four most commonly prescribed agents decreased over the study period (amoxicillin, -17.4%; erythromycin, -29.0%; trimethoprim/sulfamethoxazole, -18.7%; penicillins G and V, -19.2%). In contrast, use of newer and/or broad-spectrum agents increased (ciprofloxacin, 21.9%; cefuroxime, 30.7%; and azithromycin/clarithromycin, 29.5%). Use of second-line agents as a percentage of total antibiotic use increased from 14.4% to 19.3% between January 1995 and March 1998 (p
To evaluate the effectiveness of trimethoprim-sulfamethoxazole and fluoroquinolones in the treatment of community-acquired acute pyelonephritis.
We identified a population-based cohort of non-pregnant women aged 18-65 years, initially treated with trimethoprim-sulfamethoxazole or a fluoroquinolone for community-acquired pyelonephritis in an ambulatory care setting. Subjects were identified from a healthcare claims database in Manitoba, Canada for the period 15 February 1996 to 31 March 1999. Subsequent treatment failure, as evidenced by the provision of additional treatment up to 42 days post-diagnosis, was compared between the two treatments.
A total of 1084 women met inclusion criteria: 653 (60.2%) treated with trimethoprim-sulfamethoxazole and 431 (39.8%) treated with a fluoroquinolone. Treatment outcomes were affected by subject age. At age 20, treatment with a fluoroquinolone resulted in a reduced probability of treatment failure compared with trimethoprim-sulfamethoxazole (odds ratio, 0.56; 95% CI, 0.33-0.97). At age 60, there was no difference in the probability of treatment failure (odds ratio, 1.61; 95% CI, 0.82-3.16). No other subject characteristics impacted comparative effectiveness; however, several characteristics increased the odds of treatment failure irrespective of the initial antibiotic. These included: recent urinary tract infection (odds ratio, 2.07; 95% CI, 1.14-3.57), recent antibiotic use (odds ratio, 1.40; 95% CI, 1.00-1.96;), and a treatment duration of less than 10 days (odds ratio, 2.18; 95% CI, 1.59-2.99).
Younger subjects ( approximately 20 years) treated with fluoroquinolones were less likely to experience treatment failure than those treated with trimethoprim-sulfamethoxazole. Treatment durations of less than 10 days resulted in a higher probability of treatment failure regardless of the initial antibiotic.