The total patient population consisted of 385,461 persons, of which 82,053 were at the age of 0 to 18 years.
Of all episodes of children at the age of 0 to 18 years, 1.15% (1695 episodes) was diagnosed as a urinary tract infection (95% confidence interval [CI], 1.10–1.21).
Of all children with a urinary tract infection (n = 1460), the mean number of episodes per year was 1.2 per child, with a maximum of 5 episodes during the registration period of one year. For each episode of urinary tract infection, the mean number of consultations was 1.7, with a maximum of 13 consultations. The proportion of episodes with only one consultation was 66%.
We found an overall incidence rate of 19.0 episodes of urinary tract infections presented in general practice per 1000 person years for children under the age of 18 years (95% CI: 18.1–19.9). In other words; if 1000 children, aged 0 to 18 years, are followed for one year, their general practitioner will have made 19 times a diagnosis of a urinary tract infection. The incidence rate in girls was almost 8 times as high as in boys (respectively 34.4 episodes per 1000 person years vs. 4.4 episodes per 1000 person years, p < 0.001). Incidence rates of urinary tract infections for each year of age for both girls and boys are given in Figure . For girls the incidence gradually increased after the age of 12.
Incidence rates of urinary tract infections by age for boys and girls, 95% error bars.
Furthermore, the incidence rates varied throughout the year. A decrease of incidence rates in summertime was mainly found in children at the age of 0 to 12 years, with a range from 27 episodes in March per 1000 person years to 13 episodes in July (Figure ). The incidence rate in smaller cities and rural areas was 2.1 times as high as in the three largest cities, respectively 18.9 episodes per 1000 person years vs. 8.9 episodes per 1000 person years, p < 0.001 (Figure ).
Incidence rates throughout the year by age group, 95% error bars.
Incidence rates according to urbanisation, 95% error bars.
General practitioners prescribed medication for urinary tract infections 1776 times, to 1131 children (77% of all children in whom a urinary tract infection was diagnosed). When they chose to prescribe medication, 66% (1173 times) of the prescriptions were in accordance with the guideline of the Dutch College of General Practitioners. This percentage varied with age. The general practitioners deviated more frequently from the guideline for children under the age of 12 years than for children older than 12 years (Table ). Children approaching the age of 12 years more often received medication for urinary tract infection advised in older children, such as trimethoprim and nitrofurantoin. Differences between boys and girls in the proportion of first choice medication were statistically significant for the first three age groups (p < 0.05), favouring girls for age groups 0–2 and 2–7, but favouring boys for age group 7–12.
Number and proportion of prescriptions in accordance with the Dutch guideline for urinary tract infections, by age and sex group
In total 120 children were referred 134 times, of which 67% (90 times) to secondary care and 33% (44 times) to primary care. Of the children who should be referred according to the guideline (n= 225), only 18% (40 children) were actually referred. This percentage varied with age and gender (Table ). Especially boys under the age of 12 were seldom referred (12%).
Number of children to be referred accordancing to the guideline for urinary tract infections, and actual referrals, by age and sex group (n = 225)
The remaining 80 children had no indication for referral according to the guideline.