Health-related quality of life (HRQL) for individuals with self-reported chronic physical and/or mental health conditions: panel survey of an adult sample in the United States

Background: In the US, approximately 53% of adults have at least one chronic condition. Comorbid physical and mental health conditions often have an incremental negative impact on health-related quality of life (HRQL). Primary study objectives were to quantify the impact on HRQL of a) >= 1 physical condition, b) >= 1 comorbid mental health conditions added to a physical one, c) >= 1 mental health condition, and d) >= 1 comorbid physical conditions added to at least one related to mental health. Decrements were based on a "Healthy" reference group reporting no chronic conditions. Methods: Participants were sampled (n = 3877) from the US adult population as part of a 2009 normative survey. Demographics, number/type of chronic conditions, and HRQL data were self-reported. HRQL was defined through SF-36v2 (R) Physical Component Summary (PCS) scores and Mental Component Summary (MCS) scores. Participant "morbidity" groupings included Healthy; Physical Health Condition only, Mental Health Condition only, and Physical and Mental Health (Comorbid). PCS and MCS scores were also analyzed by physical disease clusters (e.g., cardiovascular, gastrointestinal). Multivariate regression models were used for all analyses. Results: 81% of participants were Caucasian; 9% African American. Males and females were about equally represented; 63% were >= 45 years old. The average number of reported chronic conditions was 2.4 (SD = 2.4). Relative to the Healthy group, the Physical Condition group scored 6.4 (males) and 7.5 (females) points lower on PCS. The addition of a comorbid mental health condition resulted in a total reduction of 11 points in PCS and 15 points in MCS. Compared to the Healthy group, >= 1 mental health conditions was associated with MCS decrements of 11-12 points. A physical comorbidity led to additional decrements of 3-4 points for MCS, with a total of 15 points. Incremental HRQL burden defined by both MCS and PCS scores was relatively similar across the 5 defined physical disease clusters. Conclusion: Results provide quantitative information for US adults on specific PCS and MCS score decrements associated with a comorbid condition related to mental health, as well as a comorbid condition related to physical health.