Potential drug-drug interactions in hospitalized patients with chronic heart failure and chronic obstructive pulmonary disease

Abstract

Introduction: Polypharmacy is common in patients with chronic heart failure (HF) and/or chronic obstructive pulmonary disease (COPD), but little is known about the prevalence and significance of drug-drug interactions (DDIs). This study evaluates DDIs in hospitalized patients.

Material and methods: We retrospectively screened medical charts over a 6-month period for diagnosis of chronic HF and/or COPD. Potential DDIs were evaluated using Lexi-Interact software.

Results: Seven hundred and seventy-eight patients were included in the study (median age 75 years, 61% men). The median number of drugs on admission and discharge was 6 (interquartile range (IQR) 4-9) and 7 (IQR 5-), respectively (p = 0.10). We recorded 6.5 ±5.7 potential DDIs per patient on admission and 7.2 ±5.6 on discharge (p = 0.2). From admission to discharge, type-C and type-X potential DDIs increased (p < 0.05 for both). Type X interactions were rare (< 1%), with the combination of a β-blocker and a β2 agonist being the most common (64%). There were significantly more type-C and type-D potential DDIs in patients with chronic HF as compared to patients with COPD (p < 0.001). Patients with concomitant chronic HF and COPD had more type-C and type-X potential DDIs when compared to those with individual disease (p < 0.005). An aldosterone antagonist and ACE inhibitor/ARB were prescribed to 3% of chronic HF patients with estimated glomerular filtration rate < 30 ml/(min × 1.73 m(2)).

Conclusions: The DDIs are common in patients with chronic HF and/or COPD, but only a few appear to be of clinical significance. The increase in potential DDIs from admission to discharge may reflect better guideline implementation rather than poor clinical practice.

Keywords: chronic heart failure; chronic obstructive pulmonary disease; potential drug-drug interactions.

Figure 1

Patient selection

Figure 2

Proportion of all patients (n = 778) and the number of drugs on admission and on discharge

Figure 3

Proportion of patients with chronic HF (n = 361) and number of drugs on admission and at discharge

Figure 4

Proportion of patients with COPD (n = 326) and number of drugs on admission and at discharge

Figure 5

Proportion of patients with COPD and chronic HF (n = 91) and number of drugs on admission and at discharge

Figure 6

Number of potential DDIs level C, D and X per patient on admission and on discharge in patients with COPD only, chronic HF (CHF) only and concomitant COPD and chronic HF (CHF)

Figure 7

Proportion of patients with chronic HF receiving ACE inhibitor/ARB and/or spironolactone according to the estimated glomerular filtration rate (eGRF)