Relationship between the change in mental health and indicators of medical costs in the prevention of lifestyle-related disease

Background: Mental health influences the need for health consultations, and mental healthcare is often required in the prevention of lifestyle-related disease. We investigated the relationship between indicators of medical costs and changes in mental health before and after interventions to prevent lifestyle-related disease. Methods: The study was conducted using data from participants of a lifestyle intervention program who did not have inpatient medical claims (n = 110; 46 men, 64 women). The results of a General Health Questionnaire (GHQ)-30, completed before the intervention in August 2003 and after 1 year, were used as indicators of mental health, while diagnoses based on the International Classification of Diseases (ICD)-10 from medical claims in the 2003 fiscal year were used to classify diseases using the proportional disease magnitude (PDM) method. Subjects were classified into four groups based on their change in mental health: change from good to good (GG; n = 72); change from good to poor (GP; n = 9); change from poor to good (PG; n = 16); and change from poor to poor (PP; n = 13).The indicators of medical costs were compared among four groups by analysis of variance (ANOVA) and analysis of co-variance (ANCOVA). We classified patients according to the frequency of consultations as follows: (i) those of at least two clinics per month; (ii) those of at least three clinics per month; and (iii) those of at least two clinics for the same disease per month. This frequency was used as an indicator of medical costs. Results: Patients in the GG and PG groups required significantly fewer consultations than those in the PP group. The GG group had significantly fewer patients who had at least two outpatient medical claims per month than the PP group, following adjustment for age and sex. Patients in the GG and PG groups had significantly fewer consultations for ICD-10 diagnosis codes for 'certain infectious and parasitic diseases,' 'disease of the digestive system,' and 'injury, poisoning, and certain other consequences of external causes' than those in the PP group; however, the GP group had a significantly greater number of consultations for 'endocrine, nutritional, and metabolic disease' than the PP group. Conclusion: Individuals with mental health issues both before and after intervention required more outpatient consultations than those without. The importance of considering mental health in preventing lifestyle-related diseases was confirmed.