Using electronic health record data to improve understanding of the risk of mental disorders in patients diagnosed with hypertrophic cardiomyopathy

This editorial refers to ‘Risk of incident mental disorders in hypertrophic cardiomyopathy: a nationwide propensity-matched study’, by J-B. Park et al., https://doi.org/10.1093/eurjpc/zwac260. Mental health is an important health burden with high prevalence observed in cardiovascular disease (CVD).1 There is increasing concern in the psychological aspects when treating hypertrophic cardiomyopathy (HCM), a condition affecting 1 in 200–500 adults.2–5 HCM is one of the most common genetic cardiovascular conditions, characterized by myocardial hypertrophy in the absence of abnormal loading conditions (e.g. hypertension, valve disease), which is sufficient to cause the observed abnormality.6–8 The most serious complication is sudden cardiac death (SCD) caused by ventricular arrhythmias or death after heart failure or stroke.9 HCM is the main cause of SCD in young people.7,10 With advance in early detection and treatment, HCM patients can have a nearly normal life span.11 However, living with HCM is associated with a higher prevalence depression and anxiety, which can increase the risk for SCD and HCM-related heart failure.5,12–14 The overall burden of mental disorders in HCM remains largely unknown. Most of the previous studies were limited by the small sample size or single clinical setting.5,14,15 There are paucity of data from large-scale population-based study to quantify the risk of mental disorders in patients with HCM. Recent advances in digital infrastructure and the advent of electronically available health records offer a rich resource and opportunity to comprehensively understand the scale of mental disorders at population level. In this issue of EJPC, Park et al.16 investigated the risk of incident mental disorders in patients diagnosed with HCM using nationwide population-based data between 2010 and 2016 from Korea. The diagnosis of HCM and mental disorders were defined by International Classification of Diseases, TENTH Revision, Clinical Modification (ICD-10-CM) codes. The primary outcome was the composite mood disorders, anxiety, stress-related, and somatoform disorders. The incident mental disorder was defined by hospital contacts with at least two inpatient or outpatient claims within 1 year. During a median 4-year follow-up period, there was a significantly increased risk of overall mental disorders in HCM cohort (n = 4046) compared with the propensity score matched non-HCM cohort (n = 12 139) (hazard ratio 1.72, 95% 1.60–1.86). Higher risk of mental disorders was observed in the subgroup of younger age at diagnosis and the presence of hypertension. Persistently increased risk of mental disorders was observed during the entire follow-up with the greatest risk found in the first year. Patients with mood disorders had greater risk than those with anxiety-/stress-related/somatoform disorders particularly during the first year after their diagnosis (Figure 1A). The association between the incident mental disorders and newly diagnosis of hypertrophic cardiomyopathy and breast cancer from the population-based studies. (A) Risk of incident mental disorders in different time windows after the diagnosis. (B) Risk of mental disorder associated with hypertrophic cardiomyopathy diagnosis. Data source: Park et al.16 2022: this study used nationwide population-based claims database. Mental disorder was defined by using ICD-10-CM. Suppli et al.19 2014: this study used Danish national registries between 1998 and 2011. Mental disorder was defined by ICD-8 or ICD-10. Carreira et al.18 2021: this study used UK CPRD primary care data between 1998 and 2018. Mental disorder was defined by Read code for a symptom accompanied by a prescription within 90 days. Yang et al.20 2022: this study used Taiwan National health insurance programme database and cancer registry from 1996 to 2016. Mental health disorders were defined by ICD-9-CM and ICD-10-CM. Abbreviations: ICD-9-CM. International Classification of Diseases, Ninth Revision, Clinical Modification; ICD-10-CM, International Classification of Diseases, TENTH Revision, Clinical Modification; CPRD, Clinical Practice Research Datalink. This is the first population-based study that provides the detail assessment of the risk for incident mental disorders after a HCM diagnosis, in contrast to the prevalence rates reported in most of the previous cardiovascular studies.17 The findings of increased risk for incident mental disorders in patients with HCM were comparable with the evidence from population-based data in cancer population. Several large-scale studies that examined the association between newly diagnosis of breast cancer and occurrence of mental disorders using nationwide hospital-level or primary care data from other countries showed the similar results18–20 (Figure 1B). In those studies, the risks for incident depression or anxiety were noted to be high during the first year, and risk remained elevated throughout the follow-up period18,19 (Figure 1A). Although effect size varied between studies and likely to be explained by using different diagnostic codes such as ICD code or Read code, these results support that having a newly diagnosed medical condition is related to the occurrence of mental disorders, highlighting the first year after diagnosis is a vulnerable time window. New onset mental disorder such as depression or anxiety may reflect a psychological adjustment reaction to the medical illness. Indeed, receiving a diagnosis of HCM may bring the patients with the awareness of risk of sudden death, genetic risk to offspring, need for medication, lifestyle modification, and functional limitations,3,14 which can cause considerable anxiety, emotional distress leading to the hospital contact for their mental symptoms.21,22 However, it is difficult to prove that having a diagnosis of HCM directly leads to the development of a first episode of mental disorders, because some people who had previous episode of depressive symptoms may not have it formally diagnosed until the diagnosis of HCM. The bidirectional relationship between cardiac and mental disorders may also coexist. The mechanisms explaining the link between these two clinical conditions are complex which may involve biological, behavioural, and medication-related mechanisms.1,23 The biology aspects for depression include autonomic nervous system dysfunction, elevated cortisol levels, and markers of inflammation, which make it more susceptible to cardiac arrhythmias.1,23 Mental disorders such as depression and anxiety can act as a barrier for behaviour changes, adherence to cardiovascular medication and management of cardiovascular risk factors. Some cardiovascular medications such as stains have been proven to have antidepressant effects, while others such as the benefits of beta-blockers on depression remain unclear.24,25 The main strength of this study lies in its longitudinal analysis to examine the association between the diagnosis of HCM and risk of incident mental disorders using large population-based data. Examining mental risk in different time windows after a HCM diagnosis is novel. There are several limitations when interpreting these findings. First, the mental disorders may be under detected because identification of mental disorders was based on inpatient or outpatient claims defined by ICD codes alone. There might be uncaptured cases that being managed and prescribed with medication in the primary care setting. In addition, not all individuals with mental disorders seek timely treatment, and some may do so after years.26 However, the author performed the analysis after excluding the diagnosis of a mental disorder within the first year post-HCM diagnosis, and the results remained consistent with the main analysis. Second, although the analysis has controlled baseline cardiovascular risk factors and medication, it may not capture all the clinical, social, and contextual factors that could have influenced the mental outcomes, such as severity of heart failure, family history of SCD, and family history of mental illness.3,4,27 This study is also limited by the lack of detailed time-varying confounding factors such as the progression of symptoms and treatment of insertion of implantable cardiac device during their clinical course.8,14,28,29 In sum, the findings showed newly diagnosed HCM is associated with increased risk of incident mental disorders. The rapid rise in the hospital contact for mental disorders during the first year after HCM diagnosis highlights the importance for clinical vigilance when treating HCM. Mental disorder screening along with the preventive early intervention approaches should be targeted during the early period upon the diagnosis, particularly in those diagnosed at younger age or with comorbidities. The data from the manuscript were cited from the published manuscripts.