Development and validation of the Chinese Osteoporosis Screening Algorithm (COSA) in Identification of People with High Risk of Osteoporosis

Osteoporosis is a prevalent but under-diagnosed disease partly due to the limited availability of dual-energy X-ray absorptiometry (DXA) machines in many countries. To enhance the public awareness and facilitate diagnosis of osteoporosis, we aimed to develop a new Chinese Osteoporosis Screening Algorithm (COSA) and compare its performance with the Osteoporosis Self-Assessment Tool for Asians (OSTA) to identify people at high risk of osteoporosis. A total of 4,747 postmenopausal women and men aged≥50 years from the Hong Kong Osteoporosis Study were randomly split into a development (N=2,373) and an internal validation cohort (N=2,374). An external validation cohort comprising 1,876 community-dwelling subjects was used to evaluate the positive predictive value (PPV). Among 11 predictors included, age, sex, weight, and history of fracture were significantly associated with osteoporosis after correction for multiple testing in the development cohort. Age- and sex-stratified models were developed separately for women aged<65 years, women aged≥65 years, and men due to the presence of significant sex and age interactions. The AUC of the COSA in the internal validation cohort was 0.761 (95% CI: 0.711-0.811), 0.822 (95% CI: 0.792-0.851), and 0.946 (95% CI: 0.908-0.984) for women aged<65 years, women aged≥65 years, and men, respectively. The COSA outperformed OSTA in identifying people with osteoporosis in all the three groups. In the external validation cohort, the PPV of COSA was 40.6%, 59.4%, and 19.4% for women aged<65 years, women aged≥65 years, and men, respectively. In conclusion, we have developed and validated a new osteoporosis screening algorithm, COSA, specific for Hong Kong Chinese. ### Competing Interest Statement CLC reports grants and personal fees from Amgen outside the submitted work. The other authors have nothing to declare. ### Funding Statement The study was funded by Amgen Inc. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study protocol was approved by the institutional review board of the University of Hong Kong and the HA Hong Kong West Cluster (reference: UW03-140 and UW 20-333). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors.