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Why UTIs Are Different from URIs
Abstract & commentary
By Barbara A. Phillips, MD, MSPH, Professor of Medicine, University of Kentucky; Director, Sleep Disorders Center, Samaritan Hospital, Lexington. Dr. Phillips is a consultant to Cephalon and Ventus and serves on the speakers bureaus of Cephalon and Boehringer Ingelheim.
Synopsis:For women with suspected urinary tract infection, there is no advantage to routinely sending midstream urine samples for testing; antibiotics based on dipstick tests with a delayed prescription as backup, or empirical delayed prescription, can help to reduce antibiotic use.
Source: Little P, et al. Effectiveness of five different approaches in management of urinary tract infection: Randomised controlled trial. BMJ 2010;340:c199.
This study originated in primary care practices in southern England. The authors were interested in comparing the effectiveness of different management strategies for suspected urinary tract infection (UTI). Specifically, they wanted to compare using dipstick or clinical algorithms with empirical antibiotic treatment, delayed prescribing, and targeted prescribing based on midstream urine culture results. They hypothesized that management strategies that delayed antibiotic prescription (while waiting for the results of midstream urine analysis) would have less favorable outcomes compared with an immediate antibiotic prescription.
To study this issue, general practitioners and nurses recruited women with a suspected uncomplicated urinary tract infection from clinical practices. They excluded those for whom an immediate antibiotic treatment was necessary (e.g., those who were pregnant, had pyelonephritis, nausea, vomiting, or other severe systemic symptoms), those who were older than age 75, had psychosis or dementia, or needed terminal care.
Patients were randomized to one of five basic management groups: immediate antibiotics; delayed antibiotics; symptom score (antibiotics offered if two or more of: urine cloudy on examination, urine offensive smell on examination, patient's report of moderately severe dysuria, or patient's report of nocturia); dipstick (antibiotics offered if nitrites or leucocytes and a trace of blood were detected); or midstream urine (symptomatic treatment until microbiology results available and then antibiotics targeted according to results). Self-help advice (regarding fluids, and the use of fruit juices, bicarbonate) was given to those who were not randomized to immediate antibiotics.
This protocol did allow for deviation from randomization based on patient expectations; clinicians were allowed to provide immediate antibiotics or to withhold them pending dipstick or midstream urine in situations where there were strong patient expectations. After analysis, the authors concluded that "subversion of protocol had probably not occurred."
The clinicians recorded clinical information and asked the patients to keep symptom diaries about dysuria, hematuria, frequency, "smelly urine," "tummy pain," generally feeling unwell, and restriction of daily activities. They were asked to grade the severity of symptoms as follows: 0 (no symptoms), 1 (a very slight problem), 2 (a slight problem), 3 (a moderately bad problem), 4 (a bad problem), 5 (a very bad problem), or 6 (as bad as it could be). Patients were also queried about belief in the effectiveness of antibiotics, medically unexplained somatic symptoms, and other medical problems. Patients mailed the questionnaires back when they were complete.
The investigators recruited 309 women between the ages of 18 and 70. The average duration of symptoms rated as moderately bad or worse with immediate antibiotics was 3.5 days.
Those women who delayed antibiotics for 48 hours or more, however, were likely to have 37% longer duration of symptoms rated as moderately bad, although there were no significant differences overall in symptom duration, severity of frequency symptoms, or severity of unwell symptoms between the antibiotic management strategies. Women delayed antibiotics longer in the midstream urine and the delayed groups (the average day starting antibiotics was 1.19 for immediate antibiotics, 2.18 for midstream urine, 1.43 for dipstick testing, 1.40 for symptom score, and 2.21 for delayed antibiotics). There were differences in antibiotic use (immediate antibiotics 97%, midstream urine 81%, dipstick 80%, symptom score 90%, delayed antibiotics 77%).
Of women in the midstream urine group, 66% (36/54) had a confirmed urinary tract infection. Women had similar beliefs in the effectiveness of antibiotics. There was little difference between groups for further contacts recorded in the 4 weeks after consent. Over an average follow-up of 575 days, there was no overall difference in time to reconsultation, but patients who waited for at least 48 hours before using their prescription reconsulted less. No differences in skin rash or thrush were reported. The authors estimate that modest reduction in antibiotic use (20%-25%) was achieved in all groups except the symptom score group.
The authors concluded that all five management strategies achieved similar symptom control, and that antibiotics targeted with dipstick tests with a delayed prescription as backup, or empirical delayed prescription, can help to reduce antibiotic use. They concluded that there is no advantage in routinely sending midstream urine samples for testing.
Urinary tract infections in women are a prevalent problem in primary care, probably affecting about half of women at least once in their lives.1 Urinary tract infection is distressing, and although antibiotics probably help symptoms, there is debate about whether an immediate antibiotic prescription is necessary. The authors point out that management of UTI is quite different from management of upper respiratory tract infection (URI); few URIs are bacterial whereas most suspected urinary tract infections are.2
This is the first trial comparing the commonly used management strategies of empirical delayed prescribing, targeting by dipstick, targeting by symptom pattern, or waiting for the midstream urine result, and it demonstrates that all management strategies achieve similar symptom control, so there is no advantage to routinely sending midstream urine samples for testing. In addition to expediting treatment of UTI, bypassing this approach could result in reduced use of laboratory resources.
1. Foxman B. Epidemiology of urinary tract infections: Incidence, morbidity, and economic costs. Dis Mon 2003;49:53-70.
2. Little P, et al. Developing clinical rules to predict urinary tract infection in primary care settings: Sensitivity and specificity of near patient tests (dipsticks) and clinical scores. Br J Gen Pract 2006;56:606-612.