The association between different domains of quality of life and symptoms in primary care patients with emotional disorders

Abstract

Despite the importance of quality of life (QoL) in primary care patients with emotional disorders, the specific influence of the symptoms of these disorders and the sociodemographic characteristics of patients on the various QoL domains has received scant attention. The aim of the present study of primary care patients with emotional disorders was to analyse the associations between four different QoL domains and the most prevalent clinical symptoms (i.e., depression, anxiety and somatization), while controlling for sociodemographic variables. A total of 1241 participants from 28 primary care centres in Spain were assessed with the following instruments: the Patient Health Questionnaire (PHQ)-9 to evaluate depression; the Generalized Anxiety Disorder Scale (GAD)-7 for anxiety; PHQ-15 for somatization; and the World Health Organization Quality of Life Instrument-Short Form (WHOQOL-Bref) to assess four broad QoL domains: physical health, psychological health, social relationships, and environment. The associations between the symptoms and QoL domains were examined using hierarchical regression analyses. Adjusted QoL mean values as a function of the number of overlapping diagnoses were calculated. The contribution of sociodemographic variables to most QoL domains was modest, explaining anywhere from 2% to 11% of the variance. However, adding the clinical variables increased the variance explained by 12% to 40% depending on the specific QoL domain. Depression was the strongest predictor for all domains. The number of overlapping diagnoses adversely affected all QoL domains, with each additional diagnosis reducing the main QoL subscales by 5 to 10 points. In primary care patients with a diagnostic impression of an emotional disorders as identified by their treating GP, clinical symptoms explained more of the variance in QoL than sociodemographic factors such as age, sex, level of education, marital status, work status, and income. Given the strong relationship between depressive symptoms and QoL, treatment of depression may constitute a key therapeutic target to improve QoL in people with emotional disorders in primary care.

Figure 1

The overlap of major depression, generalized anxiety and somatoform disorders (based on algorithms from the PHQ-9, GAD-7 and PHQ-15, respectively). Values indicate the percentage of the total sample (n = 1241).

Figure 2

Covariate Adjusted Means of QoL as a function of the number of mental disorder diagnoses^b. *p < 0.01; **p < 0.001. WHOQOL-Bref, World Health Organization Quality of Life Instrument-Short Form; QoL, Quality of Life. ^aMeans after controlling for covariates (age, sex, education, marital status, employment status, and income). ^bSignificance in the column ‘1 diagnosis’ refer to the difference with ‘no diagnosis’, in the ‘2 diagnoses’ column, to the difference between 2 diagnoses and 1 diagnosis, and in the ‘3 diagnoses’ column to the difference between 3 diagnoses and 2 diagnoses. Diagnoses based on algorithms from the PHQ-9, GAD-7 and PHQ-15 for major depression, generalized anxiety and somatoform disorders, respectively. ^bSE- standard errors based on 1000 bootstrap samples. ^cIn parenthesis overall score range of each subscale.