Sarah-Jo Sinnott1, Jennifer M Polinski2, Stephen Byrne3, Joshua J Gagne2. 1. Department of Epidemiology and Public Health, University College Cork, 4th Floor Western Gateway Building, Cork, Ireland. Electronic address: sarah-jo.sinnott@esri.ie. 2. Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, 1620 Tremont Street, Suite 3030, Boston, MA, 02120, USA. 3. Pharmaceutical Care Research Group, School of Pharmacy, University College Cork, College Rd, Cork, Ireland.
Abstract
OBJECTIVES: To determine the concordance between two methods to measure drug exposure duration from pharmacy claim data. STUDY DESIGN AND SETTING: We conducted a cohort study using 2002-2007 US Medicaid data. Initiators of eight drug groups were identified: statins, metformin, atypical antipsychotics, warfarin, proton pump inhibitors (PPIs), angiotensin-converting enzyme (ACE) inhibitors, nonsteroidal anti-inflammatory drugs (ns-NSAIDs), and coxibs. For each patient, we calculated two measures of exposure duration using (1) observed days' supply available in US pharmacy claims and (2) the World Health Organisation's Defined Daily Dose (DDD) methodology. We used Wilcoxon signed rank tests to compare medians and Spearman correlations to assess correlation between the two measures. RESULTS: Cohort sizes ranged from 143,885 warfarin users to >3,000,000 ns-NSAID users. Similar median exposure durations were observed for ACE inhibitors (70 days vs.75 days), PPIs (44 days vs. 45 days), and coxibs (44 days vs. 45 days). The DDD method overestimated exposure duration for ns-NSAIDs and underestimated for the remaining drug groups, relative to days' supply. Spearman correlation coefficients ranged from 0.2 to 0.8. CONCLUSION: Using DDDs to estimate drug exposure duration can result in misclassification. The magnitude of this misclassification might depend on doses used which can vary according to factors such as local prescribing practices, renal function, and age.
OBJECTIVES: To determine the concordance between two methods to measure drug exposure duration from pharmacy claim data. STUDY DESIGN AND SETTING: We conducted a cohort study using 2002-2007 US Medicaid data. Initiators of eight drug groups were identified: statins, metformin, atypical antipsychotics, warfarin, proton pump inhibitors (PPIs), angiotensin-converting enzyme (ACE) inhibitors, nonsteroidal anti-inflammatory drugs (ns-NSAIDs), and coxibs. For each patient, we calculated two measures of exposure duration using (1) observed days' supply available in US pharmacy claims and (2) the World Health Organisation's Defined Daily Dose (DDD) methodology. We used Wilcoxon signed rank tests to compare medians and Spearman correlations to assess correlation between the two measures. RESULTS: Cohort sizes ranged from 143,885 warfarin users to >3,000,000 ns-NSAID users. Similar median exposure durations were observed for ACE inhibitors (70 days vs.75 days), PPIs (44 days vs. 45 days), and coxibs (44 days vs. 45 days). The DDD method overestimated exposure duration for ns-NSAIDs and underestimated for the remaining drug groups, relative to days' supply. Spearman correlation coefficients ranged from 0.2 to 0.8. CONCLUSION: Using DDDs to estimate drug exposure duration can result in misclassification. The magnitude of this misclassification might depend on doses used which can vary according to factors such as local prescribing practices, renal function, and age.
Authors: B Wettermark; H Zoëga; K Furu; M Korhonen; J Hallas; M Nørgaard; Ab Almarsdottir; M Andersen; K Andersson Sundell; U Bergman; A Helin-Salmivaara; M Hoffmann; H Kieler; Je Martikainen; M Mortensen; M Petzold; H Wallach-Kildemoes; C Wallin; Ht Sørensen Journal: Pharmacoepidemiol Drug Saf Date: 2013-05-23 Impact factor: 2.890
Authors: Miriam Qvarnström; Thomas Kahan; Helle Kieler; Lena Brandt; Jan Hasselström; Kristina Bengtsson Boström; Karin Manhem; Per Hjerpe; Björn Wettermark Journal: Eur J Clin Pharmacol Date: 2013-07-16 Impact factor: 2.953
Authors: Félix M Arellano; Marianne Ulcickas Yood; Charles E Wentworth; Susan A Oliveria; Elena Rivero; Anila Verma; Kenneth J Rothman Journal: Pharmacoepidemiol Drug Saf Date: 2006-12 Impact factor: 2.890
Authors: Kirsten J Lum; Craig W Newcomb; Jason A Roy; Dena M Carbonari; M Elle Saine; Serena Cardillo; Harshvinder Bhullar; Arlene M Gallagher; Vincent Lo Re Journal: Eur J Clin Pharmacol Date: 2016-10-27 Impact factor: 2.953