Exploratory analysis of osteoarthritis progression among medication users: data from the Osteoarthritis Initiative.
BACKGROUND
We conducted an exploratory analysis of osteoarthritis progression among medication users in the Osteoarthritis Initiative to identify interventions or pathways that may be associated with disease modification and therefore of interest for future clinical trials.


METHODS
We used participants from the Osteoarthritis Initiative with annual medication inventory data between the baseline and 36-month follow-up visit (n= 2938). Consistent medication users were defined for each medication classification as a participant reporting at all four annual visits that they were regularly using an oral prescription medication at the time of the visit. The exploratory analysis focused on medication classes with 40 or more users. The primary outcome measures were medial tibiofemoral joint space width change and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) knee pain score change (12-36-month visits). Within each knee, we explored eight comparisons between users and matched or unmatched nonusers (defined two ways). An effect size of each comparison was calculated. Medication classes had potential signals if (a) both knees had less progression among users compared with nonusers, or (b) there was less progression based on structure and symptoms in one knee.


RESULTS
We screened 28 medication classes. Six medication classes had signals for fewer structural changes and better knee pain changes: alpha-adrenergic blockers, antilipemic (excluding statins and fibric acid), anticoagulants, selective serotonin reuptake inhibitors, antihistamines, and antineoplastic agents. Four medication classes had signals for structural changes alone: anti-estrogen (median effect size = 0.28; range = -0.41-0.64), angiotensin-converting enzyme inhibitors (median effect size = 0.13; range = -0.08-0.28), beta-adrenergic blockers (median effect size = 0.09; range = 0.01-0.30), and thyroid agents (median effect size = 0.04; range = -0.05-0.14). Thiazide diuretics had evidence for symptom modification (median effect size = -0.12; range = -0.24-0.04).


CONCLUSIONS
Users of neurovascular, antilipemic, or hormonal interventions may have less disease progression compared with nonusers.
Division of Rheumatology, Tufts Medical Center, 800 Washington Street, Box #406, Boston, MA 02111, USA.
Jeffrey B
JB
Driban
Houston Health Services Research and Development Center of Excellence, Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX, USA and Section of Immunology, Allergy, and Rheumatology, Baylor College of Medicine, Houston, TX, USA.
Grace H
GH
Lo
Departments of Family Medicine and Epidemiology, Alpert Medical School of Brown University, and Center for Primary Care and Prevention, Memorial Hospital of Rhode Island, Pawtucket, RI, USA.
Charles B
CB
Eaton
Department of Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, MA, USA.
Kate L
KL
Lapane
Department of Epidemiology and Biostatistics at the University of California, San Francisco, CA, USA.
Michael
M
Nevitt
Division of Rheumatology, Tufts Medical Center, Boston, MA, USA.
William F
WF
Harvey
Department of Epidemiology and Biostatistics at the University of California, San Francisco, CA, USA.
Charles E
CE
McCulloch
Division of Rheumatology, Tufts Medical Center, Boston, MA, USA.
Timothy E
TE
McAlindon
knee; pain; radiographs