The study was conducted as a joint venture in both the Institute of Cardiology, the National Hospital of Sri Lanka (NHSL), located in the Colombo municipal area and it is the largest, teaching and tertiary care hospital in Sri Lanka and most of the complicated and finally-referred patients were channeled, and the Diabetic Clinic, NHSL, which is one of the main specialized clinics operating in National hospital under the direct supervision of Consultant Endocrinologist with more than 100 patients’ turn over per day. The study was conducted among a study population consisted of all individuals, who were using the diabetic clinic of the National hospital of Sri Lanka. Participants were Included to the criteria of age between 40–75 years of both male and female, established type 2 diabetics of more than 5 years in duration and clinically asymptomatic patients from a cardiac standpoint. Some were excluded from the study according to the exclusion criteria of which, subjects had evidence to suggest ischemic heart disease [evidenced by classic history Electrocardiographic changes (ECG) and suggestive inducible ischemia eg. Positive treadmill test results, subjects with evidence of valvular heart disease (VHD), hypertensive patients with findings suggestive of left ventricular wall hypertrophy on transthoracic 2D echocardiography, symptomatic peripheral vascular disease fountain stage > 4, individuals who have poor echo views, end stage renal failure and any patient who detected to have evidence of VHD or ischemic heart disease (known/echo).
Though the calculated sample size for the descriptive cross-sectional study denoted as 107, the final data collection was limited to 59 participants. Using a systematic sampling method, as First person, registered or followed up to at the diabetic clinic, was selected at the entry point at pre- determined time in the morning and evening on the randomly selected day of the month, then every fifth person entered to the clinic was enrolled till the required sample size was fulfilled. A structured interviewer-administered questionnaire was used, as it was considered suitable for this study.
Most of the questions in the questionnaire were close-ended, though few were open-ended, where the anticipated variability of responses was high. Questions were arranged to achieve the specific objectives. Some questions were directly taken from the instruments used in previous studies, while some were modified and constructed by the principal investigator (PI) based on literature evidence. Questions were arranged in a way to maintain the best possible flow.
The judgmental validity of the questionnaire was tested on the face and content validity. Face validity of the questionnaire was checked by three heads from the Public, Private and Non-government organization sectors in the area and two school teachers. The content validity of the questionnaire was assessed by a Consultant Cardiologist and a Consultant Physician. Necessary amendments were made according to the suggestions and comments received(14).
It was originally constructed in the English language, but later it was translated to Sinhala and back translated to English by an independent translator to assess the back translation remained similar to the original version. Tamil translation followed with back translation were also done by two independent Tamil medical officers.
The first section assessed the personal information related to age, sex, current marital status, religion, the highest level of education, monthly personnel income, occupation, and mode of transport to the place of working / training / schooling. Secondly, the study questioned about if participants were diagnosed with having any selected chronic NCD like ischemic heart disease, chronic respiratory disease, hypertension, cancer, diabetes mellitus and stroke. Risk factors concerned to NCD were interviewed on current or previous smoking status, perception of stress at home or at work place and blood cholesterol levels.
Pretesting of the questionnaire was done by the PI among 10 individuals using a diabetic clinic in different study proper, where the study was not planned to do and the respective diabetic clinic is located in the same district but one divisional secretariat away from the Colombo municipal council, which shares much closer socio-demographic and geographic characteristics. Following pre-testing, some wording, structure and the sequence of questions were modified to make it more understandable and to maintain the flow of the questionnaire.
Data collection was done during February - August 2019 period by the principal investigator (PI) among 59 selected participants. In the sessions of morning and evening, data collection was conducted at the diabetic clinic and cardiology clinic with necessary echocardiography. Every fifth person who was entering to the diabetic clinic was interviewed by the principal investigator at a pre-determined day and time, as described in the sampling technique and most of the participants were communicated by Sinhala and a minor of the rest communicated by in English. Recruitment was continued until the sample size was completed.
Participants who were not willing to participate at the beginning but willing to be interviewed at the end of the clinic sessions were done in that way as they were resting and waited leisurely for some time after channeling the physician. Information bias was minimized by using several methods.
Approval to conduct this study and Ethics clearance (IRB) were granted by the Post Graduate Institute of Medicine, University of Colombo, Sri Lanka and the National hospital of Sri Lanka.
Protocol for Transthoracic echocardiography (TTE)
Parameters of Mitral valve pulse Doppler E, A, DT (Deceleration Time), LA volume, Medial and Lateral e’ were measured on TTE followed with presence or absence of diastolic dysfunction with the grading of the diastolic dysfunction at its presence(9, 15, 16). Structural heart diseases, systolic dysfunction, hypertensive changes, the pericardial disease were assessed.