Health-related quality of life, functional impairment and comorbidity in people with mild-to-moderate chronic kidney disease: a cross-sectional study.

ABSTRACT

OBJECTIVES: To determine the associations between comorbidities, health-related quality of life (HRQoL) and functional impairment in people with mild-to-moderate chronic kidney disease (CKD) in primary care. DESIGN: Cross-sectional analysis at 5-year follow-up in a prospective cohort study. SETTING: Thirty-two general practitioner surgeries in England. PARTICIPANTS: 1008 participants with CKD stage 3 (of 1741 people recruited at baseline in the Renal Risk in Derby study) who survived to 5 years and had complete follow-up data for HRQoL and functional status (FS). PRIMARY AND SECONDARY OUTCOME MEASURES: HRQoL assessed using the 5-level EQ-5D version (EQ-5D-5L, with domains of mobility, self-care, usual activities, pain/discomfort and anxiety/depression and index value using utility scores calculated from the English general population), and FS using the Karnofsky Performance Status scale (functional impairment defined as Karnofksy score ≤70). Comorbidity was defined by self-reported or doctor-diagnosed condition, disease-specific medication or blood result. RESULTS: Mean age was 75.8 years. The numbers reporting some problems in EQ-5D-5L domains were 582 (57.7%) for mobility, 166 (16.5%) for self-care, 466 (46.2%) for usual activities, 712 (70.6%) for pain/discomfort and 319 (31.6%) for anxiety/depression. Only 191 (18.9%) reported no problems in any domain. HRQoL index values showed greater variation among those with lower FS (eg, for those with Karnofsky score of 60, the median (IQR) EQ-5D index value was 0.45 (0.24 to 0.68) compared with 0.94 (0.86 to 1) for those with Karnofsky score of 90). Overall, 234 (23.2%) had functional impairment.In multivariable logistic regression models, functional impairment was independently associated with experiencing problems for all EQ-5D-5L domains (mobility OR 16.87 (95% CI 8.70 to 32.79, p<0.001, self-care OR 13.08 (95% CI 8.46 to 20.22), p<0.001, usual activities OR 8.27 (95% CI 5.43 to 12.58), p<0.001, pain/discomfort OR 2.94 (95% CI 1.86 to 4.67), p<0.001, anxiety/depression 3.08 (95% CI 2.23 to 4.27), p<0.001). Higher comorbidity count and obesity were independently associated with problems in mobility, self-care, usual activities and pain/discomfort for three or more comorbidities versus none (mobility OR 2.10 (95% CI 1.08 to 4.10, p for trend 0.002), self-care OR 2.64 (95% CI 0.72 to 9.67, p for trend 0.05), usual activities OR 4.20 (95% CI 2.02 to 8.74, p for trend <0.001), pain/discomfort OR 3.06 (95% CI 1.63 to 5.73, p for trend <0.001)), and for obese (body mass index (BMI) ≥30 kg/m2) versus BMI <25 kg/m2 (mobility OR 2.44 (95% CI 1.61 to 3.69, p for trend <0.001), self-care OR 1.98 (95% CI 1.06 to 3.71, p for trend 0.003), usual activities OR 1.82 (95% CI 1.19 to 2.76, p for trend 0.019), pain/discomfort OR 2.37 (95% CI 1.58 to 3.55, p for trend <0.001)). Female sex, lower FS and lower educational attainment were independently associated with anxiety/depression (ORs 1.60 (95% CI 1.18 to 2.16, p 0.002), 3.08 (95% CI 2.23 to 4.27, p<0.001) and 1.67 (95% CI 1.10 to 2.52, p 0.009), respectively). Older age, higher comorbidity count, albuminuria (≥30 mg/mmol vs <3 mg/mmol), lower educational attainment (no formal qualifications vs degree level) and obesity were independently associated with functional impairment (ORs 1.07 (95% CI 1.04 to 1.09, p<0.001), 2.18 (95% CI 0.80 to 5.96, p for trend <0.001), 1.74 (95% CI 0.82 to 3.68, p for trend 0.005), 2.08 (95% CI 1.26 to 3.41, p for trend <0.001) and 4.23 (95% CI 2.48 to 7.20), respectively). CONCLUSIONS: The majority of persons with mild-to-moderate CKD reported reductions in at least one HRQoL domain, which were independently associated with comorbidities, obesity and functional impairment. TRIAL REGISTRATION NUMBER National Institute for Health Research Clinical Research Portfolio Study Number 6632.