1. Braun J, Sieper J. Ankylosing spondylitis. Lancet 2007;369:1379–1390.
2. Shen B, Zhang A, Liu J, Da Z, Xu X, Liu H, et al. Body image disturbance and quality of life in Chinese patients with ankylosing spondylitis. Psychol Psychother 2014;87:324–337.
3. Stubbs B, Aluko Y, Myint PK, Smith TO. Prevalence of depressive symptoms and anxiety in osteoarthritis: a systematic review and metaanalysis. Age Ageing 2016;45:228–235.
4. Mak A, Tang CS, Chan MF, Cheak AA, Ho RC. Damage accrual, cumulative glucocorticoid dose and depression predict anxiety in patients with systemic lupus erythematosus. Clin Rheumatol 2011;30:795–803.
5. Zhang L, Xia Y, Zhang Q, Fu T, Yin R, Guo G, et al. The correlations of socioeconomic status, disease activity, quality of life, and depression/anxiety in Chinese patients with rheumatoid arthritis. Psychol Health Med 2017;22:28–36.
6. Liu Y, Ho RC, Mak A. The role of interleukin (IL)-17 in anxiety and depression of patients with rheumatoid arthritis. Int J Rheum Dis 2012;15:183–187.
7. Xu X, Shen B, Zhang A, Liu J, Da Z, Liu H, et al. Anxiety and depression correlate with disease and quality-of-life parameters in Chinese patients with ankylosing spondylitis. Patient Prefer Adherence 2016;10:879–885.
8. Lépine JP, Briley M. The increasing burden of depression. Neuropsychiatr Dis Treat 2011;7:3–7.
9. Durmus D, Sarisoy G, Alayli G, Kesmen H, Çetin E, Bilgici A, et al. Psychiatric symptoms in ankylosing spondylitis: their relationship with disease activity, functional capacity, pain and fatigue. Compr Psychiatry 2015;62:170–177.
10. Batmaz I, Sariyildiz MA, Dilek B, Bez Y, Karakoc M, Cevik R. Sleep quality and associated factors in ankylosing spondylitis: relationship with disease parameters, psychological status and quality of life. Rheumatol Int 2013;33:1039–1045.
12. Gunaydin R, Goksel Karatepe A, Cesmeli N, Kaya T. Fatigue in patients with ankylosing spondylitis: relationships with disease-specific variables, depression, and sleep disturbance. Clin Rheumatol 2009;28:1045–1051.
14. Aissaoui N, Rostom S, Hakkou J, Berrada Ghziouel K, Bahiri R, Abouqal R, et al. Fatigue in patients with ankylosing spondylitis: prevalence and relationships with disease-specific variables, psychological status, and sleep disturbance. Rheumatol Int 2012;32:2117–2124.
15. Hakkou J, Rostom S, Aissaoui N, Berrada KR, Abouqal R, Bahiri R, et al. Psychological status in Moroccan patients with ankylosing spondylitis and its relationships with disease parameters and quality of life. J Clin Rheumatol 2011;17:424–428.
16. Ho RC, Mak KK, Chua AN, Ho CS, Mak A. The effect of severity of depressive disorder on economic burden in a university hospital in Singapore. Expert Rev Pharmacoecon Outcomes Res 2013;13:549–559.
17. Shen CC, Hu LY, Yang AC, Kuo BI, Chiang YY, Tsai SJ. Risk of psychiatric disorders following ankylosing spondylitis: a nationwide population-based retrospective cohort study. J Rheumatol 2016;43:625–631.
18. Dhakad U, Singh BP, Das SK, Wakhlu A, Kumar P, Srivastava D, et al. Sexual dysfunctions and lower urinary tract symptoms in ankylosing spondylitis. Int J Rheum Dis 2015;18:866–872.
21. Mak A, Cheung MW, Chiew HJ, Liu Y, Ho RC. Global trend of survival and damage of systemic lupus erythematosus: meta-analysis and meta-regression of observational studies from the 1950s to 2000s. Semin Arthritis Rheum 2012;41:830–839.
25. Borenstein M, Hedges LV, Higgins JP, Rothstein HR. A basic introduction to fixed-effect and random-effects models for meta-analysis. Res Synth Methods 2010;1:97–111.
26. Cheung MW, Ho RC, Lim Y, Mak A. Conducting a meta-analysis: basics and good practices. Int J Rheum Dis 2012;15:129–135.
28. Sterne JA, Egger M. Funnel plots for detecting bias in meta-analysis: guidelines on choice of axis. J Clin Epidemiol 2001;54:1046–1055.
30. Lu Y, Mak KK, van Bever HP, Ng TP, Mak A, Ho RC. Prevalence of anxiety and depressive symptoms in adolescents with asthma: a metaanalysis and meta-regression. Pediatr Allergy Immunol 2012;23:707–715.
31. Zhang MW, Ho RC, Cheung MW, Fu E, Mak A. Prevalence of depressive symptoms in patients with chronic obstructive pulmonary disease: a systematic review, meta-analysis and meta-regression. Gen Hosp Psychiatry 2011;33:217–223.
32. Ho RC, Fu EH, Chua AN, Cheak AA, Mak A. Clinical and psychosocial factors associated with depression and anxiety in Singaporean patients with rheumatoid arthritis. Int J Rheum Dis 2011;14:37–47.
33. Hotopf M, Chidgey J, Addington-Hall J, Ly KL. Depression in advanced disease: a systematic review Part 1. Prevalence and case finding. Palliat Med 2002;16:81–97.