Hypothesis / aims of study
Several reports have suggested an association of nocturia with an increased incidence of falls and fractures. However, most of these reports are based on case series and little information is available on cohorts representative for the general population and the implications of such associations for healthcare cost. Therefore, we utilized claims data from German statutory health insurances to further explore relationships between nocturia and falls/fractures as well as their cost implications.
Study design, materials and methods
Our analysis is based on a pool of 4.85 million people enrolled in the German statutory health insurance system in 2014-2015. This data base was queried using ICD codes as surrogates for nocturia, since there is no specific code for nocturia itself (ICD Codes R35, R32, N39.3, N39.4, N32.8, F45.34), nocturia-related medications, and indicators of a tendency for falls/fractures (ICD Code R29.6). Per person data have been normalized for a 12 months period. Percent values refer to the total database.
The database included 157,076 (3.24%) patients with nocturia. Patients with nocturia had a 13% increased risk for falls compared to patients without nocturia (Table 1).
We then looked into the group of patients with a fall tendency. We found 11,695 subjects with a tendency for falls in the database, of whom 5,403 had documented falls (i.e. falls leading to a medical diagnosis). While people with a tendency for falls were older and had a greater Charlson comorbidity index, age and comorbidity were comparable in the subgroups with and without documented falls (Table 2). A high number of prescribed drugs (~10 per person) was observed in the group of patients with a tendency to fall. Presence of falls was associated with a 28% greater expenditure for hospital stay and medication.
Within the group of patients with a tendency for falls and documented falls, subjects with and without documented nocturia and subgroups of nocturia patients with and without micturition-related medication were compared (Table 3).
Within the group of patients with a tendency but not documented falls, subjects with and without documented nocturia and subgroups of nocturia patients with and without micturition-related medication were compared (Table 4).
Interpretation of results
Nocturia in itself seems to increase the risk for falls, leading to an increase in cost for statutory health insurances. Patients with a fall tendency were much older than the general population, had more comorbidities, and received more medications. Those with documented falls were not older and did not have more comorbidities but received by average one additional drug. The number of prescribed drugs per person was high in patients with fall tendency and nocturia across all subgroups. In patients with documented falls, those with additional nocturia caused more hospital and medication costs, and this was most pronounced in the subgroup with micturition-related medicines. In patient without documented falls we could not see marked difference regarding hospital and medication costs. A similar difference in healthcare cost was observed in patients with a tendency but no documented falls, but presence of micturition-related medications was not associated with a major cost difference.