title: Mini-mental state examination as a predictor of mortality among older people referred to secondary mental healthcare.
abstract: BACKGROUND
  Lower levels of cognitive function have been found to be associated with higher mortality in older people, particularly in dementia, but the association in people with other mental disorders is still inconclusive.
  
  
  RESULTS
  Data were analysed from a large mental health case register serving a geographic catchment of 1.23 million residents, and associations were investigated between cognitive function measured by the Mini-Mental State Examination (MMSE) and survival in patients aged 65 years old and over. Cox regressions were carried out, adjusting for age, gender, psychiatric diagnosis, ethnicity, marital status, and area-level socioeconomic index. A total of 6,704 subjects were involved, including 3,368 of them having a dementia diagnosis and 3,336 of them with depression or other diagnoses. Descriptive outcomes by Kaplan-Meier curves showed significant differences between those with normal and impaired cognitive function (MMSE score<25), regardless of a dementia diagnosis. As a whole, the group with lower cognitive function had an adjusted hazard ratio (HR) of 1.42 (95% CI: 1.28, 1.58) regardless of diagnosis. An HR of 1.23 (95% CI: 1.18, 1.28) per quintile increment of MMSE was also estimated after confounding control. A linear trend of MMSE in quintiles was observed for the subgroups of dementia and other non-dementia diagnoses (both p-values<0.001). However, a threshold effect of MMSE score under 20 was found for the specific diagnosis subgroups of depression.
  
  
  CONCLUSIONS
  Current study identified an association between cognitive impairment and increased mortality in older people using secondary mental health services regardless of a dementia diagnosis. Causal pathways between this exposure and outcome (for example, suboptimal healthcare) need further investigation.
authors.affiliation: King's College London (Institute of Psychiatry), London, United Kingdom; Dept of Psychiatry, Cathay General Hospital, Taipei, Taiwan; School of Medicine, Fu-Jen Catholic University, Taipei, Taiwan.
authors.forename: Yu-Ping
authors.initials: YP
authors.lastname: Su
authors.affiliation: King's College London (Institute of Psychiatry), London, United Kingdom.
authors.forename: Chin-Kuo
authors.initials: CK
authors.lastname: Chang
authors.affiliation: King's College London (Institute of Psychiatry), London, United Kingdom.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Hayes
authors.affiliation: King's College London (Institute of Psychiatry), London, United Kingdom.
authors.forename: Gayan
authors.initials: G
authors.lastname: Perera
authors.affiliation: South London and Maudsley NHS Foundation Trust, London, United Kingdom.
authors.forename: Matthew
authors.initials: M
authors.lastname: Broadbent
authors.affiliation: King's College London (Institute of Psychiatry), London, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: To
authors.affiliation: King's College London (Institute of Psychiatry), London, United Kingdom.
authors.forename: Matthew
authors.initials: M
authors.lastname: Hotopf
authors.affiliation: King's College London (Institute of Psychiatry), London, United Kingdom.
authors.forename: Robert
authors.initials: R
authors.lastname: Stewart
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003071:Cognition; D003072:Cognition Disorders / Q000401:mortality* / Q000503:physiopathology; D003704:Dementia / Q000401:mortality* / Q000503:physiopathology; D003863:Depression / Q000401:mortality* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008609:Mental Status Schedule; D009483:Neuropsychological Tests; D016016:Proportional Hazards Models; D012042:Registries; D063127:Secondary Health Care; D016019:Survival Analysis; D006113:United Kingdom / Q000453:epidemiology