Excess mortality and shortened life expectancy in people with major mental illnesses in Taiwan

Abstract

Aims Given the concerns of health inequality associated with mental illnesses, we aimed to reveal the extent of which general mortality and life expectancy at birth in people with schizophrenia, bipolar disorder and depressive disorder varied in the 2005 and 2010 nationally representative cohorts in Taiwan. Methods Two nationally representative samples of individuals with schizophrenia, bipolar disorder and depressive disorder were identified from Taiwan's national health insurance database in 2005 and 2010, respectively, and followed-up for consecutive 3 years. The database was linked to nationwide mortality registry to identify causes and date of death. Age-, gender- and cause-specific mortality rates were generated, with the average follow-up period of each age- and gender-band applied as ‘weighting’ for the calculation of expected number of deaths. Age- and gender-standardised mortality ratios (SMRs) were calculated for these 3-year observation periods with Taiwanese general population in 2011/2012 as the standard population. The SMR calculations were then stratified by natural/unnatural causes and major groups of death. Corresponding life expectancies at birth were also calculated by gender, diagnosis of mental disorders and year of cohorts for further elucidation. Results The general differential in mortality rates for people with schizophrenia and bipolar disorder remained wide, revealing an SMR of 3.65 (95% confidence interval (CI): 3.55–3.76) for cohort 2005 and 3.27 (3.18-3.36) for cohort 2010 in schizophrenia, and 2.65 (95% CI: 2.55–2.76) for cohort 2005 and 2.39 (2.31-2.48) for cohort 2010 in bipolar disorder, respectively. The SMRs in people with depression were 1.83 (95% CI: 1.81–1.86) for cohort 2005 and 1.59 (1.57-1.61) for cohort 2010. SMRs due to unnatural causes tended to decrease in people with major mental illnesses over the years, but those due to natural causes remained relatively stable. The life expectancies at birth for schizophrenia, bipolar disorder and depression were all significantly lower than the national norms, specifically showing 14.97–15.50 years of life lost for men and 15.15–15.48 years for women in people with schizophrenia. Conclusions Compared to general population, the differential in mortality rates for people with major mental illnesses persisted substantial. The differential in mortality for unnatural causes of death seemed decreasing over the years, but that due to natural causes remained relatively steady. Regardless of gender, people with schizophrenia, bipolar disorder and depression were shown to have shortened life expectancies compared to general population.

Excess mortality and life-years lost in people with bipolar disorder: an 11-year population-based cohort study

“…Our finding on all-cause SMR for bipolar disorder is broadly consistent with the literature which reported 2–3 times greater overall mortality risk than the general population (Chang et al ., 2010 ; Crump et al ., 2013 ; Laursen et al ., 2013 ; Westman et al ., 2013 ), and is in line with a recent meta-analysis reporting all-cause summary SMR of 2.05 for bipolar disorder (Hayes et al ., 2015 ). In particular, our results are similar to the findings of Taiwan studies (the only recently published Asian studies in this respect), which revealed that all-cause SMR for bipolar disorder ranged from 2.39 to 2.65 (Pan et al ., 2017 , 2020 ). Of note, although we affirmed that bipolar disorder was associated with considerably shortened life expectancy after diagnosis, our observed magnitude of longevity gap is smaller than most previous estimates based on YLLs, ranging between 10 and 15 years shorter in lifespan than the general population (Chang et al ., 2011 ; Ajetunmobi et al ., 2013 ; Laursen et al ., 2013 ; Pan et al ., 2020 ).…”

“…In particular, our results are similar to the findings of Taiwan studies (the only recently published Asian studies in this respect), which revealed that all-cause SMR for bipolar disorder ranged from 2.39 to 2.65 (Pan et al ., 2017 , 2020 ). Of note, although we affirmed that bipolar disorder was associated with considerably shortened life expectancy after diagnosis, our observed magnitude of longevity gap is smaller than most previous estimates based on YLLs, ranging between 10 and 15 years shorter in lifespan than the general population (Chang et al ., 2011 ; Ajetunmobi et al ., 2013 ; Laursen et al ., 2013 ; Pan et al ., 2020 ). Recent research, however, indicates that LYL method yields more precise, though more conservative, estimates than prior measures of reduced life expectancy by incorporating variations in age of onset of the disorder into life expectancy calculation (Erlangsen et al ., 2017 ; Plana-Ripoll et al ., 2019 ).…”

“…We observed that women, but not men, with bipolar disorder had raised cardiovascular-related SMR. This is contrary to most earlier research which found elevated mortality risk in both sexes (Ösby et al ., 2001 ; Crump et al ., 2013 ; Westman et al ., 2013 ; Pan et al ., 2020 ), although some revealed slightly higher cardiovascular mortality in women than in men (Ösby et al ., 2001 ; Crump et al ., 2013 ). A recent study further demonstrated that female patients with bipolar disorder were more likely to die of undiagnosed cardiovascular diseases than male counterparts (Heiberg et al ., 2019 ).…”

“…Bipolar disorder is a severe mental disorder which affects more than 1% of the population and constitutes one of the main causes of disability worldwide (McIntyre et al ., 2020 ). People with bipolar disorder have markedly elevated risk of premature mortality (Hayes et al ., 2015 ), with approximately 8–15-years shorter lifespan relative to the general population (Chang et al ., 2011 ; Laursen, 2011 ; Kodesh et al ., 2012 ; Ajetunmobi et al ., 2013 ; Crump et al ., 2013 ; Kessing et al ., 2015 ; Pan et al ., 2020 ). Excess deaths associated with bipolar disorder are mainly attributed to natural causes, particularly cardiovascular diseases, respiratory diseases and cancers (Crump et al ., 2013 ; Hayes et al ., 2015 ).…”

“…Notably, literature on excess mortality in bipolar disorder were mostly derived from Western countries (Hayes et al ., 2015 ) and their findings may not be generalisable to other areas owing to substantial cross-regional variation in healthcare systems, sociocultural context and population health indices. Until now, very few studies have been conducted in Asia in this respect (Saku et al ., 1995 ; Pan et al ., 2017 , 2020 ) and were limited by small sample size and short follow-up duration. In general, previous research was hampered by several important methodological constraints including sampling patients with psychiatric inpatient treatment only with subsequent bias towards greater illness severity (Saku et al ., 1995 ; Ösby et al ., 2001 ; Ajetunmobi et al ., 2013 ; Hoang et al ., 2013 ; Laursen et al ., 2013 ), lack of evaluation for cause-specific mortality (Chang et al ., 2010 ; Kodesh et al ., 2012 ; Ajetunmobi et al ., 2013 ; Medici et al ., 2015 ; Pan et al ., 2017 ; Hansen et al ., 2019 ; Lomholt et al ., 2019 ) or focus only on one specific natural cause of death for analysis (Saku et al ., 1995 ; Laursen et al ., 2013 ; Westman et al ., 2013 ; Hayes et al ., 2017 ).…”