Short versus long course antibiotic therapy for acute pyelonephritis in adults: a systematic review and meta-analysis

Acute pyelonephritis (aPN) is defined as a severe form of urinary tract infection. Despite its severity and the high incidence in the community setting, there is no consensus on the optimal duration of treatment. The aim was to compare effectiveness and tolerability of short- versus long-course treatment with the same antibiotic agent in patients with aPN. We searched MEDLINE (PubMed), EMBASE and CENTRAL up to June 2016 for randomized controlled trials (RCTs). Three pairs of authors independently extracted data and appraised risk of bias. We included 4 RCTs (439 participants). Short antibiotic treatment lasted from 4 to 14 days and long treatment from 7 to 42 days but was at least 2 days longer than the corresponding short-course. At the end of treatment, we did not find any significant differences in clinical success [risk ratio (RR) 1.01; 95% confidence interval (CI), 0.96-1.07, moderate quality evidence] as well as in microbiological success (RR 0.99; 95% CI, 0.92-1.07, very low-quality evidence). At 4-6 weeks after the end of treatment there were no significant differences in clinical relapses (RR 1.20, 95% CI 0.43-3.30, very low-quality evidence) and re-infection of other germs (RR 2.40; 95% CI, 0.68-8.49, very low-quality evidence), even if short-term therapy seemed to have more risk of recurrences (RR 2.39, 95% CI 1.19-4.83, very low quality of evidence). The incidence of any adverse effect seemed to be lower with the short-term therapy, though the results are not statistically significant (RR 0.63, 95% CI 0.39-1.02, low quality evidence). Short-term treatment for aPN seems to be equivalent to long-term treatment in terms of clinical and microbiological success at the end of treatment or tolerability. The only relevant difference is the frequency of recurrence of the same biological germ up to 4-6 weeks after the end of treatment, which is significantly higher with the short-term therapy.