Heart failure (HF) is a heterogeneous clinical syndrome characterized by symptoms of exercise intolerance. Peak oxygen consumption (VO 2peak ) is considered the gold-standard measurement of exercise/functional capacity in participants with HF; however, self-report questionnaires are frequently used to evaluate exercise/functional capacity and symptom burden for ease and clinical efficiency. , Depression or depressive symptoms is a common co-morbidity observed in HF, which may be altered during significant changes in health status. Psychophysiologic manifestations of depressive symptoms may result in differences between perceived functional ability and objective functional capacity. This study aimed to explore the relations between depressive symptoms and subjective and objective measures of exercise/functional capacity in adult patients after recent hospitalization for decompensated HF with reduced ejection fraction (HFrEF).
Secondary analysis was performed on baseline data obtained for a randomized controlled trial (NCT03797001) at a single urban academic center. Patients were recruited during hospital admission with a primary diagnosis of decompensated HFrEF and identified based on HF signs/symptoms and transthoracic echocardiogram left ventricular ejection fraction ≤40%. The secondary analysis inclusion criteria consisted of completion of cardiopulmonary exercise testing and self-administered questionnaires, including the Participant Health Questionnaire-9 (PHQ-9), Kansas City cardiomyopathy questionnaire (KCCQ), and the Duke activity status index (DASI). Objective exercise/functional capacity was measured by VO 2peak and exercise time during a symptom-limited cardiopulmonary exercise test. A peak respiratory exchange ratio (RER peak ) ≥1.0 was used to quantify acceptable effort. Additional included clinical characteristics were extracted from the study record.
Depressive symptoms were measured with the PHQ-9, a 9-item tool where higher scores indicate greater severity of depressive symptoms, with a score ≥10 considered clinically significant for depressive symptoms. Subjective functional capacity was assessed using the KCCQ–physical limitation (PL) domain and the DASI. The KCCQ is a 23-item tool separated into multiple subdomains that assess different aspects of health status, with each subdomain scaled from 0 to 100. The KCCQ clinical summary and overall summary scores were also included in the analysis. The DASI is a 12-item tool consisting of specific activities of daily living weighted based on the metabolic cost and scaled from 0 to 58.2. For KCCQ and DASI, higher scores indicate better perceived exercise/functional capacity. All participants provided written informed consent before study entry, as approved by the local institutional review board.
Data are presented as means (SD) or numbers (%). Pearson correlation coefficients were used to assess the relations between continuous variables. The analysis of covariance was used for group comparisons between participants with PHQ-9 scores < or ≥10 for VO 2peak , exercise time, RER peak , KCCQ-PL, and DASI scores (reported as adjusted mean difference [95% confidence interval (CI)]). Data were analyzed using IBM SPSS Statistics v29.0 (IBM Corporation, Armonk, NY), with significance set at p ≤0.05.
A total of 101 patients (aged 56 [SD 12] years, 36% women, 74% Black) were included in the study. The mean PHQ-9 score was 7.97 (SD 6.7) and 34 patients (34%) met the criteria for clinically significant depressive symptoms ( Figure 1 ).
A total of 7 participants (7%) were taking antidepressant medications at baseline visit. The mean DASI score was 28.4 (SD 15.8), KCCQ-PL score was 63.6 (SD 25.7), and VO 2peak was 13.6 (SD 4.1) ml⋅kg −1 ⋅min −1 . The PHQ-9 scores had a moderate inverse correlation with the DASI ( R = −0.355, p <0.001), KCCQ-PL, KCCQ clinical summary, and KCCQ overall summary scores ( R = −0.437, R = −0.629, R = −0.560, all p <0.001, respectively). No association was observed between PHQ-9 and effort-dependent exercise variables (VO 2peak [ R = −0.065, p = 0.517], RER peak [ R = 0.039, p = 0.702], or exercise time [ R = −0.079, p = 0.430]). Peak VO 2 was moderately correlated with the KCCQ-PL ( R = 0.322, p = 0.001) and DASI ( R = 0.320, p = 0.001) scores.
When grouped as those without or with clinically significant depressive symptoms ( Table 1 ), there was a significant group difference for DASI (10.1, 95% CI 4.0 to 16.1, p = 0.001) and KCCQ-PL scores (22.1, 95% CI 12.8 to 31.4, p <0.001) but not for VO 2peak (−0.6, 95% CI −2.4 to 1.2, ml⋅kg −1 ⋅min −1 , p = 0.536), RER peak (−0.03, 95% CI −0.08 to 0.02, p = 0.238), or exercise time (21, 95% CI −102 to 60 seconds, p = 0.605).
| Total | PHQ-9 <10 | PHQ-9 ≥10 | |
|---|---|---|---|
| Variables | N=101 | n=67 | n=34 |
| Left-ventricle ejection fraction (%) | 28 (8) | 29 (7) | 26 (8) * |
| Body Mass Index (kg/m 2 ) | 33.7 (8.0) | 33.7 (8.2) | 33.8 (7.8) |
| Cardiopulmonary Exercise Test variables | |||
| Peak respiratory exchange ratio | 1.16 (0.10) | 1.15 (0.10) | 1.17 (0.11) |
| Exercise time, seconds | 450 (182) | 462 (197) | 422 (147) |
| Physical activity (MET/min/week) | 1669 (3637) | 1267 (1988) | 2461 (5588) |
| Duke Activity Status Index | 28.4 (15.8) | 32.2 (15.0) | 21.1 (15.1) * |
| Kansas City Cardiomyopathy Questionnaire | |||
| Physical Limitation domain | 63.6 (25.7) | 71.5 (23.8) | 47.9 (22.0) * |
| Overall Summary Score | 50.7 (21.6) | 59.9 (19.5) | 33.2 (12.9) * |
| Clinical Summary Score | 57.9 (22.8) | 66.7 (20.5) | 40.9 (16.8) * |
| Medications | |||
| Antidepressants | 7 (6.9%) | 3 (4.5%) | 4 (11.8%) |
| Beta Blockers | 56 (55%) | 37 (55%) | 19 (56%) |
| ACE/ARB/ARNI | 63 (63%) | 41 (61%) | 20 (59%) |
| MRA | 25 (25%) | 15 (22%) | 9 (27%) |
| SGLT2 inhibitor | 14 (14%) | 9 (13%) | 4 (12%) |
| Hydralazine | 16 (16%) | 12 (18%) | 3 (9%) |
| Isosorbide nitrates | 15 (15%) | 14 (21%) | 2 (6%) * |
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