Prevalence, Risk Factors and Pain Subtypes of Post-COVID Pain in Nonhospitalized Older Adults: A Cross-Sectional Study

Background: Post-COVID pain (PCP) is a condition that ensues from an infection of coronavirus disease 2019 (COVID-19). Some researchers have explored the prevalence of PCP and its characteristics in the individuals who experience it. However, most individuals involved in the previous studies were middle-aged, and those studies focused mainly on hospital patients and musculoskeletal PCP. Existing data on PCP and its subtypes among older adults and outpatients are scanty. Objective: Our study aims to identify PCP's prevalence and associated risk factors and to compare the quality of life (QoL), sleep quality, and anxiety and depression levels in nonhospitalized elderly COVID-19 survivors with different PCP subtypes. Study Design: A cross-sectional study. Setting: The study was conducted from April 2023 to June 2023 after the first outbreak of the Omicron variant of SARS-CoV-2 in the Taikang Yanyuan Continuing Care Retirement Community (CCRC) in China. Methods: Eligible participants were surveyed using the Numeric Rating Scale (NRS), Douleur Neuropathique-4 questionnaire (DN4), EuroQol 5D-5L questionnaire (EQ-5D-5L), Pittsburgh Sleep Quality Index (PSQI), Generalized Anxiety Disorder 7 (GAD-7) scale, and Patient Health Questionnaire-9 (PHQ-9) scale. COVID-19 symptoms and laboratory parameters were obtained through an electronic healthcare system. Descriptive analysis was performed based on the presence of PCP and PCP subtypes. Multivariable logistic regression analysis and multiple linear regression were used for risk-factor analysis and adjustment of confounding factors. Results: A total of 668 individuals (female: 59.3%, median age: 84 years) who had been infected with COVID-19 for a median duration of 145 (126-168) days were enrolled in our study. PCP was observed in 9.4% (63/668) of elderly COVID-19 survivors. Number of COVID-19 symptoms (aOR 1.31, 95%CI 1.05-1.64, P = 0.018) and previous chronic pain (aOR 4.24, 95%CI 1.59-11.27, P = 0.004) were risk factors associated with PCP. Individuals with neuropathic PCP exhibited higher NRS scores (5 [5-6] vs. 3 [3-4], P < 0.001) and more use of analgesic drugs (70.0%, 7/10 vs. 20.8%, 11/53, P = 0.005) for pain management. Neuropathic PCP was associated with lower scores on the EQ-5D index (B = -0.210, 95% CI -0.369 to -0.051, P = 0.011) and EQ-VAS (B = -10.808, 95% CI -21.149 to -0.468, P = 0.041) and higher PHQ-9 scores (B = 3.154, 95% CI 0.674-5.634, P = 0.014). Limitations: It is difficult to establish a strong causality between PCP and SARS-CoV-2 infection due to the study's cross-sectional nature. Selection bias could not be eliminated, since our study relied on volunteer participation. Due to neuropathic PCP's lower prevalence than nonneuropathic PCP, larger sample sizes and multicenter studies are crucial for a comprehensive understanding of the neuropathic PCP condition. Conclusion: Our study found a PCP prevalence of 9.4% in nonhospitalized older adults who had survived COVID-19. Number of COVID-19 symptoms and history of previous chronic pain seemed to be potential risk factors for PCP. Neuropathic PCP was associated with lower QoL and a more severe depression level.