Quality of life and comorbidity among older home care clients: role of positive attitudes toward aging

PURPOSE: Comorbidity has a negative impact on quality of life (QoL). This study aimed to investigate whether the impact of comorbidity on QoL is lower in older home care clients with positive attitudes toward aging. METHODS: Totally, 361 older adults aged 50–91 years who were clients of 14 home care agencies in two regions in the Czech Republic gave an in-person interview to research nurses and completed the WHOQOL-BREF, the WHOQOL-OLD, and the Attitudes to Aging Questionnaire. The Charlson comorbidity index was calculated using ICD-10 codes. To address possible interaction between comorbidity and attitudes toward aging for QoL, the presence of additive interaction between comorbidity and attitudes toward aging on QoL was examined by synergy index. All analyses were adjusted by age, gender, education, and living arrangement. RESULTS: A higher comorbidity index was significantly associated with lower scores of both QoL measures; one index increase was associated with 3.7 [95 % confidence interval (CI) 1.5: 5.9] decreases in generic QoL and 3.6 (95 % CI 1.3: 5.9) decreases in older-specific QoL. In stratified analyses by attitudes toward aging, comorbidity showed no association with QoL among those with positive attitudes, while it was significantly associated with low QoL in those without positive attitudes. The presence of additive interactions between comorbidity and less than positive attitudes on falling in low QoL was clearly suggested. CONCLUSIONS: The negative impact of comorbidity on QoL might be mitigated by promoting a positive self-perception of aging in older people. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11136-014-0899-x) contains supplementary material, which is available to authorized users.