Study site, design and participants: The current study was conducted among patients seeking psychiatric care at the out-patient facility of the Schizophrenia Research Foundation (SCARF) in Chennai, India. It was a cross- sectional observational study, carried out between July 2017 and November 2017.

Male and female patients aged 18 years and above with known psychiatric illness and being treated at SCARF were consecutively selected for the study during their visit. Those who consented to be part of the study were included, irrespective of the type of psychiatric diagnosis, duration of psychiatric disease, type of comorbid physical NCD(s) or use of psychotropic medications.

Sample size estimation: We used the method outlined by Naing et al. to estimate sample size.¹⁸ The sample size was estimated using the formula: n=Z2*P*(1-P)/d², where n is sample size, Z is Z statistic for a level of confidence (we used Z value of 1.96 for 95% confidence level), P is the expected prevalence or proportion (in proportion of one; if 20%, P = 0.2), and d is precision (in proportion of one; if 5%, d = 0.05). Based on a pilot study of 91 patients, we estimated prevalence of atleast 1 NCD to be 30.8%. Using this estimate in the above formula, we obtained a sample size of 328 patients.

Data collection: A survey questionnaire was developed based on the WHO STEP-wise approach to surveillance methodology, a standardized method to collect, analyze and disseminate data on risk factors for NCDs, especially in low-to-middle income countries.¹⁹ The questionnaire included socio-demographic characteristics, current psychiatric diagnoses, duration of psychiatric disease, use of psychotropic medications, known medical history of physical NCDs such as hypertension, diabetes mellitus, heart disease, chronic lung disease, or renal disease, details on how/where these comorbidities were diagnosed, pharmacological management of these comorbidities and the associated treatment duration. Further, information on family history of psychiatric illness or physical NCDs and lifestyle such as diet modifications, physical activity, smoking and alcohol intake were collected. Anthropometric measurements such as height, weight, waist and hip circumference were performed using a non-stretchable tape. Blood pressure (BP) was measured in the right arm using standard cuffs fitted with a mercury sphygmomanometer in sitting position.

Patients were interviewed in the local language by a trained medical doctor and responses to the interview were patient-reported or caregiver-reported in case the patient was absent. Psychiatric diagnoses of the patients were obtained from their electronic medical records available at the outpatient center. These diagnoses had been previously recorded by the treating psychiatrist at the time of patient registration and treatment initiation. Diagnostic categories were identified by the treating psychiatrist based on ICD-10 codes F01-F99 and used for analysis.²⁰ Psychotropic medications prescribed to the patients were recorded based on their prescriptions. For the analysis, these medications were classified into four categories, namely patients taking: (1) one antipsychotic (either first- or second-generation); (2) more than one type of antipsychotic; (3) antipsychotic medications combined with other psychotropic medications (eg. benzodiazepines, mood stabilizers, anti-depressant drugs, anti-epileptics drugs, anticholinergics); and (4) other medicines or combinations which do not fall in the first three categories (eg. Combinations based on mood stabilizers, benzodiazepines and/or anti-depressants).

Data analysis: STATA (release 15.1, Texas, USA: Stata Corp) was used for all statistical analyses. Statistical differences in the socio-demographic and clinical characteristics between patients with and without diabetes/hypertension were tested using Chi-square test or Fisher’s exact test (as appropriate) for categorical data and Student’s t-test or Mann-Whitney test (as appropriate) for continuous data. Similarly, the association of diabetes/hypertension with different psychiatric diagnoses and the use of various psychotropic medications were tested using a Chi-square test or Fisher’s exact test (as appropriate). A p-value less than 0.05 was considered statistically significant.

Ethics: The study obtained all required ethical approvals from the Institutional Review Board at SCARF and informed consent was taken individually from all participants.

This study is one amongst the few conducted in India to explore frequency of concurrent physical comorbidities such as diabetes, hypertension, chronic lung disease, chronic kidney disease or heart disease in a large cohort of 450 patients with a wide spectrum of psychiatric illnesses in an out-patient tertiary care setting, as elicited by a history . Approximately 25% of these patients self- reported the presence of at least one of these physical comorbidities. Diabetes was the most prevalent comorbidity, as reported by 15.8% of patients, followed by hypertension in 8.7% of patients. Psychiatrists at the tertiary care center played a limited role in management of these comorbid physical NCDs. Finally, the psychiatric out-patient facility has a potential for opportunistic screening for common physical NCDs such as diabetes or hypertension as 40 patients with elevated BP or at risk for hypertension were identified while conducting a physical examination as part of this study.

Other studies in India have found higher prevalence rates of medical comorbidity than the prevalence observed in our study.14-17,21Singh et al. conducted a study in a setting very similar to ours, except for the fact that clinical examination and investigations were conducted to identify various physical comorbidities. Close to half the patient population (48%) had physical illnesses, with hypertension (29.1%), respiratory diseases (15%), and diabetes (10%) amongst the most common diseases.16 Although not comparable, the difference in rates observed between our study and Singh et.al. could partly be explained by the fact that we depended on patient-reported presence of the illness(es), and not clinical investigations, thereby leading to under-reported rates. It is possible that the under-reporting could be due to lack of disease awareness, communication difficulties or hesitancy. In fact, previous studies have shown that psychiatric patients have difficulties in communicating their physical illnesses to the physician.22 Furthermore, it has been suggested that such difficulties are constant and not reduced in non-acute conditions.

In our study, majority of patients with diabetes or hypertension were diagnosed with schizophrenia, schizotypal and delusional disorders. It has been well- documented that patients with schizophrenia suffer a high burden of diabetes and metabolic syndrome, and a higher prevalence compared to the general population.23 It is to be noted that an increase in well-known risk factors in these patients partially explains most of the increased risk.4 In our study, too, we identified some of these risk factors such as age, family history of diabetes or hypertension and duration of psychiatric illness of 5 years or longer, to be associated with the presence of diabetes or hypertension.

Our study showed that less than 8% of patients were being treated for diabetes or hypertension at our tertiary care center, and less than 20% of patients were referred by a psychiatrist for further follow-up with respect to management of diabetes, hypertension or other physical illnesses. These results suggest that psychiatrists need to be more aware of management of common physical comorbidities such as diabetes and hypertension in patients with psychiatric illnesses. Patients often seek treatment for symptoms of disorders that are diagnosed as co-morbid, rather than principal conditions. As a complex interface exists between such physical and mental illnesses, psychiatrists need to be trained to treat patients with these common physical conditions, and in specific, severe mental illnesses. In this manner, improved screening and early treatment of physical illnesses in psychiatric patients can significantly impact their psychosocial functioning and quality of life.

Interestingly, through monitoring of BP during a patient’s visit to our OP facility, we identified as many patients at risk of hypertension with elevated BP (≥140 and/or ≥90 mmHg) as the number of patients with self-reported hypertension. In essence, this finding exemplifies the importance of regular physical examination and appropriate investigations at a tertiary psychiatric care center that in turn, can identify patients at risk of developing or already have diabetes, hypertension or MetS. Importantly, this observation highlights the potential of opportunistic screening of common physical NCDs in a psychiatric care center. In fact, a nurse-led intervention at a community mental health center resulted in 30% more patients with severe mental illness who received screening for CVD risk factors such as blood pressure, cholesterol, glucose, BMI and smoking status.24This indicates that care coordination, or integrated care programs for physical health conditions in patients with mental illnesses can better-equip health systems and be more effective in reducing unfavourable health outcomes in these patients.

In the present study, the patients were recruited from a psychiatric out-patient facility. The findings of this study cannot be generalized to the entire population as these rates were based on patient-reported presence of the physical NCD and a wide-spectrum of psychiatric diagnoses were present in our study population. Further, we are not aware of the diagnostic criteria or tests used by the medical doctor to diagnose the patient with diabetes and/or hypertension. In this study, no laboratory diagnosis to confirm of the NCDs were done as the out- patient mental health clinic caters to patients who may not be able to afford laboratory expenses. Our findings need to be confirmed in larger community-based studies and also, by conducting clinical investigations to diagnose physical illnesses, especially in those who are at greater risk for cardiovascular disease. However, this study also demonstrates that a good clinical history for NCDs can provide valuable information to direct management of psychiatric patients, mental health professionals can be enabled to be aware of NCDs in patients and make appropriate referrals.

In conclusion, approximately 25% of patients visiting a tertiary psychiatric care center self-reported the presence of diabetes or hypertension. This study shows that physical examination andfamilial history can be helpful in detecting psychiatric patients at risk of developing physical NCDs in such a clinical setting. It is crucial for psychiatrists to increase their involvement in managing comorbid physical NCDs or for existing health systems to set up a referral path way to improve overall health outcomes for patients with psychiatric illnesses. Future studies are needed to identify potential differences that need to be incorporated while treating patients with physical NCDs based on the presence/absence of psychiatric illnesses. Studies are also required to develop a comprehensive psychosocial intervention strategy for patients with physical and mental comorbidities where lifestyle modifications are integrated within.