[1] Univ Putra Malaysia, Fac Med & Hlth Sci, Dept Family Med, Serdang, Selangor, Malaysia
[2] Univ Putra Malaysia, Malaysian Res Inst Ageing MyAgeing, Serdang, Malaysia
[3] Univ Malaya, Fac Med, UMeHlth Unit, Kuala Lumpur, Malaysia
[4] Univ Malaya, Fac Med, Dept Primary Care Med, Kuala Lumpur, Malaysia
[5] Univ Edinburgh, Usher Inst, NIHR Global Hlth Res Unit Resp Hlth RESPIRE, Edinburgh, Midlothian, Scotland
[6] Hosp Pusrawi Sdn Bhd, Kuala Lumpur, Malaysia
[7] Univ Malaya, Fac Med, Dept Social & Prevent Med, Ctr Epidemiol & Evidence Based Practice, Kuala Lumpur, Malaysia
[8] Minist Hlth Malaysia, Klin Kesihatan Bandar Bot, Kiang, Selangor, Malaysia
[9] Univ Edinburgh, Usher Inst, Edinburgh Clin Trials Unit, Edinburgh, Midlothian, Scotland
[10] Univ Malaya, Fac Med, Dept Med, Kuala Lumpur, Malaysia
[11] UCSI Univ, Fac Business & Management, Kuala Lumpur, Malaysia