Principle findings
We presented the first study that investigate the associations between having mental disorder and cascade of care in managing four common physical NCDs in China among older adult population in China. Our study revealed that having mental disorder was associated with increased odds of being aware of having dyslipidemia, and kidney disease, after adjusting for covariates including frequency of outpatient visit. Additionally, having mental disorder was associated with increased odds of receiving treatment of hypertension, but not for diabetes, dyslipidemia, and kidney disease. However, having mental disorder was not associated with increased or decreased odds of being controlled for hypertension, diabetes, dyslipidemia and kidney disease.
Comparison with literature
The finding on the positive effect of having mental health conditions on better diagnosis of previously undiagnosed dyslipidemia and kidney disease is consistent with the small number of existing articles. Subjects with more comorbidities likely resulted in having more frequent visits to and interactions with multiple health providers,5,17,27-29 such as dyslipidemia, and kidney disease in this particular study. Having more comorbidities and increased frequency of healthcare visits were likely associated with a greater tendency for patients to self-report kidney pain and test blood liquid 30,31.
Studies examined the relationship between comorbid health condition and NCD treatment have shown conflicting results which may reflect complexity of the issue5,17,32-35 It is worth noting that our study considered only whether subjects were taking treatment or not, and did not if treatment was adequate, in terms of adherence to medication.5,17,36 While our study showed that subjects with mental disorder have higher odds of taking treatment, but in reality, with more co-occurring physical conditions, the odds of treatment adherence and having adequate treatment would decline.5,17
The finding on having mental health conditions not associated with increased or decreased odds of being controlled for hypertension, diabetes, dyslipidemia and kidney disease is not consistent with the little amount of existing literature. The difficulty in controlling NCDs tend to be exacerbated with having more co-occurring physical chronic conditions.9,11,15
There has been debate in the recent literature on how co-occurring conditions influence the management and control of NCDs.5,17 Magnan et al (2014) analysed electronic health data records of 24,430 adults aged 18 to 75 years from the United States, and revealed that even though having more concordant NCDs were correlated with a higher likelihood of achieving diabetes control goals, this relationship was not present for the outcome on achieving blood pressure control.16 Ricci-Cabello et al (2015) investigated the prevalence of concordant and discordant NCDs of diabetes, and their impact on diabetes care in England.5,14 The study revealed that only 2 of 8 discordant NCDs to diabetes were correlated with worse quality of diabetes care, and only 4 of 7 concordant NCDs with diabetes were correlated with better quality of diabetes care.14
Hence, this study along with our previous work and other papers, provide further evidence on the complexity of how co-occurring mental health conditions impact the management and control of NCDs, and the hypothesis that concordant comorbidities with mental illness facilitate the management of NCDs and discordant comorbidities with mental illness impede the management of NCDs may be over-simplified.5,17
Strengths and limitations
This is the first study that used a large population of adults from China with multimorbidity, to investigate the association between having mental health conditions with the odds of being undiagnosed, untreated and uncontrolled for co-occurring physical chronic condition.
Self-reported diagnosis of chronic conditions may be under-reported especially among the lower socioeconomic groups in China.37-39 Additionally, stigma could be a reason for under-reporting of depression in MICs.40,41 However, our study utilized clinical measurement for all physical NCDs as well as mental disorder which can mitigate under-reporting of NCDs. 42
Additionally, this survey only asked if subjects were taking treatment (medicines, lifestyle changes), but did not measure self-reported treatment adherence (i.e. dosage, frequency, duration, etc).17,36 Biomarkers used to assess whether chronic conditions were controlled may not be sufficiently comprehensive, and supplemental assessment criteria may have been needed for better accuracy. However, this survey is one of the few existing surveys that utilised biomarkers, rather than only symptom-based assessment via questions.5,17
Future studies could expand on this study by examining more NCDs, especially conditions with high prevalence and morbidity.5,17,43 The study’s cross-sectional design means that causality could not be determined, and studies that use cohort study designs could examine how mental health conditions lead to worse treatment and control of physical chronic diseases in subjects that are followed-up over a decade.5,17,33
Clinical, policy, and research implications
Clinical guidelines must be updated to include improved screening and treatment of physical chronic conditions that may occur in patients with mental health conditions.5,17 Regarding poorer treatment and control of mental health conditions and physical chronic diseases associated with having more NCDs, clinical guidelines could incorporate more intentional monitoring of patients’ adherence to medication and treatments by clinicians.5,17 Also proposed in our previous work, current clinical guidelines are based on evidence from controlled trials for treating single NCDs,5,17,44-46 and treatments may no longer be effective and even have adverse effects when applying single-disease guidelines to patients with multimorbidity.5,17,47 Hence, clinical guidelines should be tailored towards an approach to multimorbidity of co-occurring mental illness and physical chronic conditions, whereby clinicians review the effectiveness and risks of combining the medications and different treatments for mental illness and physical chronic diseases.4,5,17,44
Healthcare systems in LMICs like China may need to implement policies that improve access to care from the primary care system for continual treatment after first diagnosis.48-51 Policies that prioritise NCD combinations that include mental health conditions that are more prevalent or associated with poorer management and control need be considered, such as reducing costs of medicines and clinic visits.35,52 It is worth noting that health-care delivery in China is hospital-centered and fragmented, with little coordination among health-care providers across different tiers of the system53. Strong primary health care, underpinned by multidisciplinary teams lead by general practitioner, is also crucial for the improved prevention and treatment of patients with multiple NCDs. Health care delivery need to shift away from the current vertical approach of treating single-disease models to the one that emphasize on horizontal integration that aims to provide more effectively management for patients with multiple NCDs, including co-existing physical and mental NCDs. Overall, our study provides evidence on the impact of comorbid mental health condition on the management of physical NCDs in China. Further research is required to better understand the epidemiology of co-existing mental-physical NCDs and associated impacts on management of the conditions and associated costs and health outcomes in LMIC settings.