Electronic Thesis and Dissertation Repository


Doctor of Philosophy


Family Medicine


Stewart, Moira

2nd Supervisor

Ryan, Bridget


3rd Supervisor

Fortin, Martin


Université de Sherbrooke



Multimorbidity is common. The gaps in multimorbidity research are in the measurement of the prevalence, the levels of multimorbidity and its associated outcomes.

This thesis aimed to provide a uniform definition for multimorbidity, identify instruments for measuring the level of multimorbidity, and describe patient-reported outcomes for different levels of multimorbidity.

Three studies were conducted. The first determined the prevalence rates of multimorbidity and explored whether there were differences among the different age, gender and ethnic groups in the primary care population. Common dyads and triads of conditions were described. The systematic review updated the list of instruments for measuring the level of multimorbidity for community-dwelling adults. The third study determined the association of different levels of multimorbidity with depression, anxiety and quality of life. The agreement between patients’ self-reported conditions and conditions recorded in their electronic medical records (EMR) were reported.

Increasing age was associated with a higher prevalence of multimorbidity. The commonest dyad was hyperlipidaemia/hypertension, and triad was hyperlipidaemia/hypertension/diabetes. Disease count and weighted indices were the most commonly used instruments for measuring the level of multimorbidity. Self-reported disease count was positively associated with depression and anxiety, and negatively associated with quality of life. Stroke was the only condition that showed substantial agreement between patients’ self-reported medical conditions and the EMR.

We identified a practical definition of multimorbidity in the Singapore primary care population, described the commonly used instruments for measuring the level of multimorbidity, and reported the disparity of multimorbidity outcomes between patients’ self-reported chronic conditions and EMR.