Discussion
Using the target trial emulation framework, we observed that attending GOPC within 30 days after discharge from a COVID-19 episode is associated with a better survival in 1 year among older adults with multimorbidity. Moreover, the results of our sensitivity analysis demonstrate that the sooner the visit to the GOPC within 20–60 days after discharge, the more likely the patient survives within the observation period. This range of grace period was identified as optimal because it balanced the need for timely follow-up with the practical considerations of scheduling and patient recovery.25 26 The findings are robust across various subgroups and different operationalisations of multimorbidity. Subgroup analysis showed that the benefits of timely follow-up care were widely applicable to patients with different characteristics, especially high-risk groups with characteristics such as having four or more baseline chronic diseases, being over 95 years old or not fully vaccinated. For regular GOPC attendees before the pandemics, resuming to visit GOPC for health management shortly after discharge from the COVID-19 hospitalisation significantly improves the survival in 1 year. Our findings provide novel real-world evidence that a primary care consultation shortly after a COVID-19 episode might increase the survival in Chinese older people aged 85 years or above.
The majority of preceding studies have primarily focused on investigating the effect of specialised rehabilitation interventions of particular post-COVID-19 symptoms on COVID-19 patients.27 For example, Lesley et al conducted a literature review indicating that pulmonary rehabilitation intervention can alleviate post-COVID-19 symptoms among elder people over 60 years old.28 Most of these studies are case reports or clinical randomised trials with a limited sample size of less than 100 participants. Furthermore, the outcomes they explored were mainly the relief of post-COVID-19 symptoms, and there was a lack of observation of long-term, more severe outcomes. Additionally, previous investigations have predominantly concentrated on assessing the effectiveness of specific rehabilitation interventions, most of which are not commonly practised in primary care settings. Our study, in contrast, is the first territory-wide evaluation of real-world primary care on severe outcome, that is, mortality, among older people who are most at risk after discharge from COVID-19. Adapting the target trial emulation design, we have mitigated the issue of immortal time bias that frequently arises in this type of real-world research and have accounted for a wide range of covariates, considering the multimorbidity of the elderly population.
In spite of the clear strengths of this study, there are several limitations to note while interpreting the results. First, indication bias has been reduced using the clone-censor-weight approach but has not been entirely eliminated. There is a possibility that individuals who were able to access GOPC services were inherently characterised by a better overall health status and a better health awareness. However, our sensitivity analysis, which focused exclusively on individual who had records of regular GOPC visits before COVID-19 pandemic, yielded highly comparable results. Second, the presence of unobserved confounders poses another limitation. Factors such as disease severity, lifestyle choices, disability status, socioeconomic circumstances and the accessibility of care in different locations may affect the outcomes. Also, it is worth mentioning that while those who are older and more multimorbid prefer to visit the public sector for primary care,29 the attendance of patients in the private sector could introduce confounding factors that were not accounted for in this study. Our study population predominantly represents older adults using the Hong Kong public healthcare system, which acts as a safety net for uninsured or financially disadvantaged individuals. Despite this, many people with chronic conditions stay in the public system due to its affordability and high-quality services.30 Thus, our cohort is socioeconomically diverse and representative of the general older population in Hong Kong. Moreover, while our study predominantly focused on a Chinese population, the principles of primary care management and the benefits of timely follow-up visits are universally applicable. However, healthcare systems, cultural contexts and patient behaviours vary significantly across different regions. For example, the centralised and publicly funded healthcare system in Hong Kong ensures relatively uniform access to primary care services like GOPCs. In contrast, countries with less integrated healthcare systems might experience different outcomes due to disparities in access to care.31 Therefore, caution should be exercised when generalising the results to other populations. To enhance the external validity of the findings, it is necessary to conduct further replications of similar analyses in other populations and settings.
Consistent with previous research, we observed a significant association between receiving follow-up care at the primary care level shortly after respiratory infection hospitalisation and improved health outcomes.32 This association can plausibly be attributed to several important pathways. First, timely primary care follow-up facilitates the monitoring and management of symptoms after respiratory infection hospitalisation, leading to symptoms alleviation and reducing the risk of further development of complications.33 Second, early identification of potential problems allows healthcare providers to address any emerging conditions promptly, preventing serious adverse events and promoting optimal recovery.34 35 Third, according to the National Institute for Health and Care Excellence (NICE) guideline, general practice assesses patients’ baseline multimorbidity during their first follow-up visit and then develops patient-centred, multidisciplinary rehabilitation support.36 For example, respiratory rehabilitation therapy is recommended for patients with previous neurological and muscular comorbidity.37 Finally, the enhancement of self-management specific to the current diseases or symptoms through primary care follow-up empowers patients to actively participate in their own healthcare and achieve improved outcomes.38 39
According to our findings, the current evidence is in favour of recommendations that healthcare systems implement timely primary care follow-up mechanisms specifically for older individuals following a COVID-19 hospitalisation. This targeted approach aims to reduce the risk of death in this most vulnerable population. One potential strategy is to develop protocols for healthcare providers involved in the care of patients with COVID-19 to ensure that primary care services/follow-up care is provided within a specified time interval after discharge. By prioritising and facilitating primary care follow-up, healthcare systems can effectively support the recovery and well-being of older adults with multimorbidity, and likely extend the life expectancy despite having experienced a severe episode of COVID-19.
Additionally, it is crucial to extend primary care services to support older people in the community as far as possible. Expanding primary care in community settings allows for a patient-centred approach to healthcare delivery. For example, implementing various forms of home care to ensure accessibility and convenience of older patients,40 which can enhance the continuity of healthcare and facilitate early intervention should any health problem arise.
In conclusion, our study demonstrated that receiving follow-up care at the primary care level shortly after COVID-19 hospitalisation significantly improve survival and achieve better health outcome. Future research should focus on assessing the effectiveness of expanding the primary care services to support community-based older populations.
