Population-based epidemiological analysis of acute pyelonephritis and antibiotic prescription in Spain (2009-2018)

To estimate the incidence of pyelonephritis in primary care in Spain from 2009 to 2018, assess the associated antibiotic prescriptions, and analyse trends by sex and age.

This is a retrospective observational population-based national study using the Database for Pharmacoepidemiological Research in the Public Domain (BIFAP), which contains primary care electronic medical records, and is representative of the Spanish population. Patients with a diagnosis of pyelonephritis were included. Sociodemographic and clinical data were collected. Crude and adjusted incidence rates were calculated per 10,000 person-years by sex and age, and annual and global percentages of antibiotic use were calculated by sex, age, and antibiotic group. Trend analysis was performed using a joinpoint regression model.

24,888 cases of pyelonephritis were recorded with an incidence of 4.2/10,000 person-years (6.6 women vs 1.5 men). An annual decreasing trend was observed in women (AAPC average annual percentage change) -2.7 (95% CI -4.4;-0.9), men -3.0 (95% CI -4.5;-1.5), patients aged 18-64 years -2.9 (95% CI -4.7;-0.9) and ≥ 65 years -4.2 (95% CI -5.8;-2.4). The most frequently used groups of antibiotics were cephalosporins (38.7%), quinolones (30%), combined penicillins (22.2%) and fosfomycin (6.8%). Cephalosporin prescription predominated in women (39.8%), and quinolone prescription in men (40.3%). The most prescribed cephalosporins were third and second generation (21% and 17.7% respectively). A downward annual trend was observed in the global use of antibiotics AAPC -0.8 (95% CI -1.4; -0.2), with an increasing AAPC 1.7 (95% CI -0.6; 3.4) in ≥65 years. Among the groups of antibiotics, the prescription of quinolones AAPC -6.9 (95% CI -31.7;17.3) and penicillins AAPC -8.7 (95% CI -11.2;-6.8) decreased and cephalosporins increased AAPC 19.0 (95% CI 12.2;26).

Women had a fourfold higher incidence of acute pyelonephritis than men, with a decreasing trend over the study period. Cephalosporins were the most commonly prescribed antibiotics in women, while quinolones were more common in men. An increasing trend in cephalosporin use and a decreasing in quinolone use were observed.