1. Department of Rheumatology and Immunology, Singapore General Hospital, Singapore
2. Duke-NUS Medical School, Singapore
3. Yong Loo Lin School of Medicine, National University of Singapore, Singapore
4. Health Services Research Unit, Singapore General Hospital, Singapore
5. Centre for Quantitative Medicine, Duke-NUS Medical School, Singapore
6. Department of Statistics and Applied Probability, National University of Singapore, Singapore
7. Department of Biostatistics and Bioinformatics, Duke University, Durham, NC, USA