Table 1. Harmonizing measures from the CARRS and MASALA studies.

Measure	Methodology in CARRS	Methodology in MASALA	Harmonized measure
Income	Monthly household income (categories)	Annual household income (categories)	Compare individuals in top tertile of income versus not
Physical activity	International Physical Activity Questionnaire (IPAQ)[37]	Typical Week’s Physical Activity Questionnaire[38]	Weekly vigorous physical activity (yes/no), since both surveys described vigorous physical activity similarly
Diet	Frequency of consumption of major food groups for the past year (including typical foods consumed in India)	Study of Health Assessment and Risk in Ethnic Groups (SHARE) questionnaire[39]	Fruit and vegetable intake (number of times/day), since both surveys described these food groups similarly
Blood pressure	After 5 minutes of rest, Seated blood pressure at rest at least two times, using an oscillometric device (Omron Dailan Co., Ltd, Dalian, Liaoning, China). A third measurement was obtained if the difference between the first two systolic or diastolic measurements was more than 10 mmHg and 5 mmHg, with at least 30 seconds in between each.	After 5 minutes of rest, seated blood pressure at rest three times with at one minute in between each reading, using an oscillometric device (V100 Vital Signs Monitor, GE Healthcare, Fairfield, CT. U.S.)	Average of last two readings
Medications	Obtained 1 year after baseline; individual medication names	Obtained at baseline; individual medication names	Categorized by study investigators into broader categories (yes/no): 1.Blood pressure medications, 2. ACEI/ARB therapy, 3. Anti-glycemic therapy, including insulin, and 4. Lipid therapy, including statins, fibrates and ezetimibe
Chronic kidney disease	Spot urine albumin measured via immunoturbidimetric assaySerum and urine creatinine measured via rate-blanked compensated kinetic Jaffe method	Spot urine albumin measured via immunoturbidimetric assay	Creatinine assays in both laboratories traceable to IDMS. CKD defined in both studies as: 1. Single urine albumin to creatinine ratio ≥ 3.4 mg/mmol [30 mg/g], or 2. Single calculation of CKD-EPI eGFR < 60 ml/min/1.73m2
		Serum and urine creatinine measured via enzymatic colorometric method

Abbreviations: IDMS- isotope dilution mass spectrometry; CKD-chronic kidney disease; eGFR-estimated glomerular filtration rate.