Mortality and secular trend in the incidence of bipolar disorder

TY - JOUR

T1 - Mortality and secular trend in the incidence of bipolar disorder

AU - Medici, Clara Reece

AU - Videbech, Poul

AU - Gustafsson, Lea Nørgreen

AU - Munk-Jørgensen, Povl

N1 - Copyright © 2015 Elsevier B.V. All rights reserved.

PY - 2015/9/1

Y1 - 2015/9/1

N2 - Abstract Background The world-wide interest in bipolar disorder is illustrated by an exponential increase in publications on the disorder registered in Pubmed since 1990. This inspired an investigation of the epidemiology of bipolar disorder. Methods This was a register-based cohort study. All first-ever diagnoses of bipolar disorder (International Classification of Diseases-10: F31) were identified in the nationwide Danish Psychiatric Central Research Register between 1995 and 2012. Causes of death were obtained from The Danish Register of Causes of Death. Age- and gender standardized incidence rates, standardized mortality ratio (SMR) and Kaplan-Meier survival estimates were calculated. Results We identified 15,334 incident cases of bipolar disorder. The incidence rate increased from 18.5/100,000 person-years (PY) in 1995 to 28.4/100,000 PY in 2012. The mean age at time of diagnosis decreased significantly from 54.5 years in 1995 to 42.4 years in 2012 (p<0.001). The mean time from first affective diagnosis to diagnosis of bipolar disorder was 7.9 years (SD 9.1). The SMR was 1.7 (95%-CI 1.2-2.1). Causes of death were mainly natural; 9% died from suicide. Limitations Only patients in psychiatric care were included. The outpatient registry opened in 1995. Patients treated solely in outpatient units are not recorded previously. Systematic studies validating all the clinical diagnoses of the registry do not exist. Conclusions The incidence of bipolar disorder has increased in the last 10 years. The SMR was significantly increased. Half of the patients were known to have another affective disorder. This should be considered in future decisions regarding the healthcare organization.

AB - Abstract Background The world-wide interest in bipolar disorder is illustrated by an exponential increase in publications on the disorder registered in Pubmed since 1990. This inspired an investigation of the epidemiology of bipolar disorder. Methods This was a register-based cohort study. All first-ever diagnoses of bipolar disorder (International Classification of Diseases-10: F31) were identified in the nationwide Danish Psychiatric Central Research Register between 1995 and 2012. Causes of death were obtained from The Danish Register of Causes of Death. Age- and gender standardized incidence rates, standardized mortality ratio (SMR) and Kaplan-Meier survival estimates were calculated. Results We identified 15,334 incident cases of bipolar disorder. The incidence rate increased from 18.5/100,000 person-years (PY) in 1995 to 28.4/100,000 PY in 2012. The mean age at time of diagnosis decreased significantly from 54.5 years in 1995 to 42.4 years in 2012 (p<0.001). The mean time from first affective diagnosis to diagnosis of bipolar disorder was 7.9 years (SD 9.1). The SMR was 1.7 (95%-CI 1.2-2.1). Causes of death were mainly natural; 9% died from suicide. Limitations Only patients in psychiatric care were included. The outpatient registry opened in 1995. Patients treated solely in outpatient units are not recorded previously. Systematic studies validating all the clinical diagnoses of the registry do not exist. Conclusions The incidence of bipolar disorder has increased in the last 10 years. The SMR was significantly increased. Half of the patients were known to have another affective disorder. This should be considered in future decisions regarding the healthcare organization.

KW - Aged

KW - Bipolar Disorder

KW - Causality

KW - Cause of Death

KW - Cohort Studies

KW - Denmark

KW - Female

KW - Humans

KW - Incidence

KW - International Classification of Diseases

KW - Kaplan-Meier Estimate

KW - Male

KW - Middle Aged

KW - Mood Disorders

KW - Registries

KW - Suicide

KW - Young Adult

U2 - 10.1016/j.jad.2015.04.032

DO - 10.1016/j.jad.2015.04.032

M3 - Journal article

C2 - 26001661

SN - 0165-0327

VL - 183

SP - 39

EP - 44

JO - Journal of Affective Disorders

JF - Journal of Affective Disorders

ER -