| Primary |
| 1. What is the relative financial contribution of prescription medications to incident HCU expenditures and how do they compare with non-HCUs? |
Prescription medication costs will rank within the top 3 cost categories of HCU expenditures Average medication costs (on an individual level) and the proportion of costs attributable to medications (at a population level relative to total costs) are different in HCUs and non-HCUs In a subset of incident HCUs, prescription medication costs alone will be greater than the financial threshold for HCU status
| Retrospective matched cohort analysis (HCU status treated as an “exposure”) |
Annual total prescription medication costs (co–primary outcome) Annual drug cost to total health care expenditure ratio (co–primary outcome) Frequency of patient cases in which annual drug costs alone exceeds health expenditure threshold for HCU status
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| 2. What is the relative clinical contribution of prescription medications to incident HCU status? (i.e., Does the quality of medications prescribed and used contribute to differences in health care costs and HCU development?) |
The use of “high quality” medication classes (i.e., those with a strong evidence base for primary or secondary prevention selected a priori for analysis) will be associated with a decreased odds of incident HCU status The use of “potentially inappropriate or high risk” medications selected a priori for analysis will be associated with an increased odds of incident HCU status The use of “high cost (per unit)” medications for recognized indications will be associated with an increased odds of incident HCU status
| Case–control analysis (HCU status treated as an outcome) |
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| Secondary |
| 3. What is the relative difference in clinical profiles of newly incident HCUs v. non-HCUs including diagnoses, medications and prognosis? |
Incident HCUs will have a significantly higher prevalence and baseline burden of chronic condition diagnoses and prescription drug use compared with non-HCUs Incident HCUs will have a significantly higher annual risk of mortality and hospital admissions compared with non-HCUs
| Retrospective matched cohort analysis (HCU status treated as an “exposure”) |
Number of Johns Hopkins Adjusted Diagnosis Groups and Expanded Diagnosis Clusters Number of unique prescription drug classes dispensed All-cause mortality rate All-cause hospital admission rate
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| 4. What is the prevalent use of prescription medication classes with a strong evidence base for primary or secondary prevention of complications associated with the most common chronic conditions? |
| Retrospective matched cohort analysis (HCU status treated as an “exposure”) |
Prevalent use of “high quality” medication classes selected a priori for analysis Prevalence of relevant chronic condition based on John Hopkins Expanded Diagnosis Clusters and chart-validated ICES chronic disease cohorts
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