Hospital admissions related to medication : prevalence, provocation and prevention

Medication is one of the most commonly applied medical interventions in healthcare and has been shown to improve health and quality of life. Unfortunately it can also do harm and can cause severe adverse events like hospitalisations. The focus in this thesis is on medication related hospital admissions: the magnitude of the problem, the associated provoking factors and the prevention of these admissions. The first study we conducted was the multicenter HARM (Hospital Admissions Related to Medication) study in 21 hospitals in the Netherlands. A case-control design was used to determine risk factors for potentially preventable admissions. This study shows that 5.6% of all unplanned admissions were medication related of which almost half (46.5%) were potentially preventable. The main determinants of preventable medication-related hospital admissions were impaired cognition (odds ratio, 11.9; 95% confidence interval (CI), 3.9-36.3), 4 or more comorbidities (8.1; 3.1-21.7), dependent living situation (3.0; 1.4-6.5), impaired renal function (2.6; 1.6-4.2), non-adherence to the medication regimen (2.3; 1.4-3.8) and polypharmacy (2.7; 1.6-4.4). Impaired renal function was not only a risk factor but 70 admissions (10%) were related to renal impairment and a medication error. HARMs are not only a burden to patients and their relatives but also to society, involving high costs. Combining the medical costs and those of production losses resulted in average costs of €6009 for one, potentially preventable, medication-related hospital admission for all ages. The identified risk factors provided a starting point for preventing medication-related hospital admissions in our second study the PHARM (Preventing Hospital Admissions by Reviewing Medication) study. This study was a controlled, multi-centre study in an integrated primary care setting. We included only patients with a high risk of a HARM. The intervention, the pharmaceutical care process, consisted of a pharmaceutical anamnesis, a pharmacotherapy review, a pharmaceutical care plan and the monitoring and follow up evaluation of the care plan. We aimed to include 14200 patients, 7100 in each arm, from at least 142 pharmacies but experienced many difficulties in including patients. Eventually 364 intervention and 310 control patients were included in 42 primary health care settings of at least one pharmacist and at least two GPs. More medication related hospital admissions were found in the control group than in the intervention group; respectively 10 and 6 admissions. The effect was dependent on the number of diseases. The HR (Hazard Ratio) of the intervention for 3 diseases was 0.77 (95% CI: 0.17-2.59); for 4 diseases 0.43 (95%CI: 0.093-1.20); for 5 diseases 0.28 (95% CI: 0.056-0.73); for 6 diseases 0.19 (95% CI: 0.033-0.53); for 7 diseases 0.14 (95% CI: 0.020-0.43) and for 8 diseases 0.11 (95% CI: 0.013-0.34). Between the intervention and control group no statistically significant differences were found in the secondary outcomes survival, adverse drug events and quality of life. With these results we demonstrated that the patient’s own pharmacist together with its own GP and the patient may prevent hospital admissions with a medication related cause but the pharmaceutical care process is difficult to implement in an ordinary primary care setting