Risk and clinical predictors of osteoporotic fracture in East Asian patients with chronic obstructive pulmonary disease: a population-based cohort study.
BACKGROUND
Osteoporosis is becoming an impending epidemic in the Asia-Pacific region. The association between risk of osteoporotic fracture (OTPF) and chronic obstructive pulmonary disease (COPD) in East Asian patients is yet to be fully examined. We conducted a nationwide population-based retrospective cohort study of 98,700 patients aged ≥50 years with or without COPD using a national administrative claims dataset.


METHODS
The patients were divided into COPD and comparison groups comprising 19,740 and 78,960 patients, respectively. The groups were 1 to 4 matched for age, gender, index date, diabetes mellitus, pre-existing osteoporosis and chronic kidney disease. Information such as the geographic area where southern part represented more sunshine exposure, smoking-related diagnoses, alcohol use disorder, whether there was regular use of inhaled corticosteroids and oral corticosteroids, vitamin D prescriptions, Charlson-Deyo comorbidity index score, and other relevant medical comorbidities were extracted for analysis. They were followed up until OTPF or the end of the year 2013. The outcome measure was an osteoporotic vertebral fracture and other long-bone fractures. A multivariate Cox model was constructed to derive adjusted hazard ratios (aHR) for OTPF with corresponding 95% confidence intervals (CI) after controlling for age, sex, insurance premium category, vitamin D prescription, osteoporosis, and coronary heart disease (CHD). Kaplan-Meier curves of the probability of OTPF-free survival for each cohort were compared using the log-rank test. Patients with OTPF during the first follow-up year were excluded from the overall risk calculation. Contributing factors to the increased risk of OTPF in COPD patients were examined in a sensitivity analysis.


RESULTS
After a total follow-up of 68,743 patient-years for the COPD group and 278,051 patient-years for the matched comparison group, the HR for OTPF was 1.24 (95% CI [1.02-1.51];P= 0.0322) in COPD patients. The aHR was increased by 30% for vertebral OTPF (aHR = 1.297, 95% CI [1.020-1.649];P= 0.0339). Differential lag time sensitivity analysis revealed a progressively elevated risk up to 8-fold increase in women (aHR = 8.0 (95% CI [1.81-35.4];P< 0.01)) during the fifth follow-up year. COPD patients with pre-existing osteoporosis or given vitamin D prescription harbor a sustained increased risk up to the 5th (aHR, 4.1; 95% CI [1.61-10.35]) and third (aHR, 2.97; 95% CI [1.48-5.97]) follow-up year, respectively.


CONCLUSIONS
Our nationwide population-based cohort study demonstrates that East Asian COPD patients aged 50 and beyond do harbor a modestly increased risk for osteoporotic vertebral fractures particularly for those who are female, have pre-existing osteoporosis or require vitamin D prescription.
Department of Geriatric Medicine, Kuang Tien General Hospital, Taichung, Taiwan; Jen-Te Junior College of Medicine, Nursing and Management, Miaoli County, Taiwan.
Ping-Hsueh
PH
Lee
KTGH Cancer Center, Kuang Tien General Hospital, Taichung, Taiwan; Department of Bioinformatics and Medical Engineering, Asia University Taiwan, Taichung, Taiwan; Disease Informatics Research Group, Asia University Taiwan, Taiwan.
Victor C
VC
Kok
Department of Computer Science and Information Engineering, National Central University , Jhongli , Taoyuan , Taiwan.
Po-Liang
PL
Chou
Jen-Te Junior College of Medicine, Nursing and Management, Miaoli County, Taiwan; Department of Diagnostic Radiology, Kuang Tien General Hospital, Taichung, Taiwan.
Ming-Chang
MC
Ku
Department of Bioinformatics and Medical Engineering, Asia University Taiwan, Taichung, Taiwan; Disease Informatics Research Group, Asia University Taiwan, Taiwan.
Yu-Ching
YC
Chen
Department of Bioinformatics and Medical Engineering, Asia University Taiwan, Taichung, Taiwan; Disease Informatics Research Group, Asia University Taiwan, Taiwan; Department of Computer Science and Information Engineering, National Central University, Jhongli, Taoyuan, Taiwan.
Jorng-Tzong
JT
Horng
Asian; COPD; Longitudinal study; Osteoporosis; Osteoporotic fracture; Population-based study; Retrospective cohort study; Vertebral fracture; Vlinical predictors