Hypothesis / aims of study
Urinary tract infections (UTI) are thought to account for approximately 20% of all hospitalizations in the first year after a diagnosis of neurogenic lower urinary tract dysfunction (NLUTD).[1] This study aims to characterize the incidence and severity of UTI (i.e., UTI-related hospitalizations) among intermittent catheter (IC) users with neurogenic and non-neurogenic diagnoses.
Study design, materials and methods
Health insurance claims data from the IBM MarketScan Database between January 1, 2015 – December 31, 2019 was retrospectively analyzed. MarketScan is a health insurance claim database, which includes commercial Preferred-Provider Organization (PPO) and Medicare supplemental claims, including drug coverage benefits. Three comparator groups were created: (a) IC users with NLUTD, (b) IC users without neurogenic bladder (non-NLUTD), and (c) age-and-sex-matched members of the general population with no IC use (GEN). Claims were followed for one year following initiation of IC utilization, or one year following a randomly selected index date for the general population comparator group. UTI claims were identified based on primary or secondary diagnosis codes. UTI incidence, hospitalizations and length of hospital stay were compared using Chi Square analysis. Kaplan Meier curves were further used to analyze time to UTIs, comparing all patients in the NLUTD and Non-NLUTD groups to 1:1000 general population data. Analysis was also stratified based on the number of UTI claims (0 UTI, 1 UTI, 2 UTI, 3+ UTI).
Results
Claims were identified for 6,944 IC using NLUTD patients, 5,102 non-NLUTD IC using patients, and 4,715,1055 members of the general population who did not use IC. The annualized incidence of UTI in those performing self-catheterization was 54.94% in NLUTD patients and 38.93% in non- NLUTD patients as compared to 9.8% in the general population not performing IC (p<0.001 between each of the three groups). Of all patients with UTI, 20.63% of the NLUTD patients were hospitalized for UTI treatment, compared to 10.32% non-NLUTD patients and 6.77% general population (p <0.001 for each of the comparisons between groups). Average length of stay in the hospital (in days) was greater for those with NLUTD compared to non-NLUTD (2.22± 3.63 days versus 1.54± 2.05 days, p<0.001). Seventeen percent of NLUTD patients experienced 3+ UTIs compared to 9.56% non-NLUTD patients (p<0.001) and NLUTD patients made up 70.85% of all IC users experiencing 3+ UTIs. The figure shows incidence of inpatient hospitalization requiring UTI treatment during the first year after initiation of IC utilization in NLUTD patients (compared to general population; HR = 18.189, 95% CIs [16.934, 19.538]) and non-NLUTD patients (compared to general population; HR = 6.172, 95% CIs [5.377, 7.084]).
Interpretation of results
NLUTD and non-NLUTD patients experienced approximately 5.5- and 4-times higher rate of UTIs during the first year of using ICs compared to the general population not using ICs, respectively. Both NLUTD and non-NLUTD patients that use IC have a very high risk of hospitaliation for UTIs compared to the general population. NLUTD patients are twice as likely to be hospitalized for UTI treatment than non-NLUTD patients and the average length of stay was 42% greater in NLUTD patients. NLUTD patients were approximately twice as likely to experience 3 or more UTIs comparing to non-NLUTD patients. These results point towards a higher burden of UTI among IC users, and particularly those with NLUTD.