Mental disorders, chronic physical conditions subtract from number of years in perfect health

Mental disorders and chronic physical conditions represent a serious public health burden in Singapore, with chronic pain, major depressive disorder (MDD), obsessive compulsive disorder (OCD), cardiovascular disease (CVD) and generalized anxiety disorder (GAD) being the top five contributors to increased number of years lived with disability in the general population, according to a recent study.

“As the population in Singapore is rapidly ageing with a growing chronic disease burden, data on current disease burden in terms of quality-adjusted life year (QALY) losses due to chronic physical and mental disorders are important tools for monitoring the burden of these conditions on the population,” the authors said. [J Affect Disord 2013;190:326-332]

“A QALY is a summary measure that combines the length of survival of an individual and the health-related quality of life by placing a value on time spent in different health states… For example, a person with full health has a utility score value of 1, while a health state equivalent to being dead is given a value of 0,” they added. [Health Policy Plan 2006;21:402-408; Value Health 2009;12:S27-S30; Health Technol Assess 2014;18:1-188]

The current study used data from the second Singapore Mental Health Study (SMHS-2016) and included 6,126 adults, among whom 6,113 (50.5 percent female) completed the 12-item Short Form Health Survey (SF-12). Majority of the population were female (50.5 percent), aged between 18 and 49 years (60 percent), Chinese (75.7 percent), employed (72 percent) and currently married (60 percent).

QALYs lost were estimated by calculating the SF-6D scores derived from the 12-item Short Form Health Survey. Utility scores generated by the SF-6D ranged from 0.29–1.00, with 1.00 representing full health and 0.29 representing the worst possible health state. The mean SF-6D score in the population was 0.87.

Among individuals with mental disorders, GAD was associated with the largest reduction in SF-6D scores (β, –0.136; p<0.001), followed by MDD (β, –0.097; p<0.001), alcohol abuse (β, –0.07; p=0.006), bipolar disorder (β, –0.06; p=0.02) and OCD (β, –0.058; p<0.001). [Sci Rep 2020;10:2695]

On the other hand, ulcer produced the largest reduction in SF-6D scores (β, –0.09; p<0.001) among individuals with chronic physical conditions. Next to it was lung disease (β, –0.076; p=0.001), chronic pain (β, –0.06; p<0.001) and CVD (β, –0.042; p<0.001).

At the population level, chronic pain and MDD were associated with the greatest QALY loss (14,204 and 6,889 respectively). The former was the primary driver of burden among individuals aged ≥35 years, while MDD exerted the greatest impact among those aged 18–34 years.

“[I]n multiple linear regression model, we found younger age, female gender, unemployment, and lower income were significantly associated with lower utility scores,” the authors said.

“Our findings are consistent with local data which found that the prevalence of mental disorders was higher among those of younger age, and mental disorders represented the largest single contributor to the disease burden of disability-adjusted life years for Singaporeans between the ages of 10 and 34 years,” they pointed out, underscoring the need for initiatives promoting mental well-being and to develop effective treatment strategies to improve young people’s mental health. [Epidemiol Psychiatr Sci 2019;29:e29; https://www.moh.gov.sg/resources-statistics/singapore-burden-of-disease-report-2017]

Aside from mental disorders, chronic pain and CVD also deserve to be prioritized public health prevention programmes, the authors added.