gms | German Medical Science

Background: Polypharmacy has become the rule rather than an exception in older people, and is a key risk factor for serious adverse drug events (ADEs), such as drug-related hospital admissions. In view of ageing populations, policy and research efforts have increased in recent decades to reduce the inappropriate use of polypharmacy. Evaluations of such interventions have, however, typically focused on changes in medication use processes rather than clinical outcomes. In previous work, we have developed indicators of potentially drug-related hospital admissions. These include for example gastrointestinal (GI) bleeding, which is one of the most common reasons for such hospital admissions and can be measured in routine data (e.g. from health insurance providers), making it potentially suitable as a measure of drug therapy safety in outpatient care. Thus, the aim of this study is to estimate the prevalence and time trends of GI bleeding that led to hospital admission with potential high-risk medication in two Scottish health boards between 2010 and 2020.

Materials and methods: We conduct a retrospective population-based repeated cross-sectional study in an electronic population-based database holding patient level data of residents in two neighbouring Scottish health regions (NHS Tayside and NHS Fife) to estimate the age-sex standardized prevalence of GI bleeding as a potentially drug-related hospital admission. Potentially drug-related hospital admissions are those where a patient is admitted with the respective adverse event (i.e. based on relevant ICD-10 codes being documented as “main condition” or based on laboratory data) and the patient has been dispensed a potentially causally linked drug or drug combination in the 90 days prior to admission. For GI bleeding the potentially causal medication includes non-steroidal anti-inflammatory drugs, oral anticoagulants and antiplatelets. For each year we calculate the proportion (%, 95% confidence interval) of the adult population (aged 40 years or older), who had been admitted to hospital for GI bleeding (with high-risk medication) or had been prescribed at least one potentially causal drug (regardless of the occurrence of GI bleeding). We also determine time points with significant changes in trends of this outcome by using joinpoint regression.

Results: We identified a change in trend regarding prescription safety in 2013. While prescriptions of high-risk medicines decreased, the number of prescriptions of proton pump inhibitors (PPIs), which can reduce the risk of GI bleeding, increased. This explains the greater decrease in prescriptions for high-risk medication without concomitant PPI prescriptions, although the change in trend only became apparent in 2018. The prevalence of GI bleeding (with high-risk medication) also changed its trend in 2018 (Table 1 [Tab. 1]). This “period of latency” is conclusive, as changes in drug therapy safety (here shown as the occurrence of potentially drug-related hospital admissions) can only become apparent after changes in prescribing behaviour. Thus, it may be assumed that drug therapy safety has improved in the last decade with regard to GI bleeding.

Conclusion: In order to assess the effectiveness of initiatives to improve drug therapy safety, the development of measuring instruments is essential. Our study provides insights into the prevalence and influenceability of potentially drug-related hospital admissions. Comparisons with data from Germany may identify potential improvements for both health systems.