Abstract
This study analyzes whether the lowered blood pressure threshold for hypertension in the 2017 American College of Cardiology/American Heart Association guidelines vs the JNC7 guidelines are associated with diagnosis prevalence of hypertension among adults in India.
In India, ischemic heart disease is the leading cause of death and premature death, and high blood pressure (BP) is the fourth leading risk factor of death and disability.1 In a recent study in JAMA Internal Medicine, Geldsetzer et al2 reported the first national prevalence rate of hypertension in India to be 25%, based on a systolic BP of 140 mm Hg or higher or a diastolic BP of 90 mm Hg or higher, as defined in the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure guidelines (JNC7).3 In 2017, the American College of Cardiology/American Heart Association (ACC/AHA) Task Force on Clinical Practice Guidelines reduced the systolic BP and diastolic BP threshold for stage 1 hypertension to 130/80 mm Hg and recommended the initiation of BP-lowering medication if the patient’s 10-year risk for cardiovascular disease (CVD) is 10% or greater or if the patient has known clinical CVD, diabetes, or chronic kidney disease.4 The objective of the present study was to estimate the difference in hypertension prevalence in India depending on whether the JNC7 or the ACC/AHA guidelines were applied.
Methods
This study was exempt from review by the institutional review board of the Harvard T.H. Chan School of Public Health and the institutional ethics committee of the Public Health Foundation of India, as the study was a secondary analysis of data available in the public domain. Data analysis was conducted from February 4, 2018, to February 14, 2018.
We used data from the District-Level Household Survey-4 (DLHS4) and the Annual Health Survey (AHS) carried out between 2012 and 2014 in all of the 29 states, except Jammu, Kashmir, and Gujarat, and 5 of the 7 union territories in India. During the surveys, each household member aged 18 years or older, excluding pregnant women, underwent 2 BP measurements while seated; an electronic sphygmomanometer was used on the left arm, and the 2 readings were taken at least 3 minutes apart. Hypertension was determined using the mean of the 2 readings, according to JNC7 or ACC/AHA guidelines. Hypertension prevalence was weighted to the age structure of India’s population in 2013. The difference in hypertension prevalence, overall and by demographic and socioeconomic subgroups, was estimated. The 10-year risk for CVD was calculated using the Framingham office-based CVD risk score among those aged 30 to 74 years with ACC/AHA stage 1 hypertension. The details of this analysis are published elsewhere.2
Results
A total of 1 387 680 (85.7%) of the 1 619 230 adults interviewed (733 617 [52.9%] were female and 654 063 [47.1%] were male, with a mean [SD] age of 41 [15.9] years) had nonmissing systolic and diastolic BP values. The overall hypertension prevalence increased from 302 514 (21.8%; 95% CI, 21.5%-22.1%) following the JNC7 guidelines to 725 756 (52.3%; 95% CI, 51.9%-52.8%) following the ACC/AHA guidelines, resulting in a relative increase of 140%. Among those aged 30 to 74 years with ACC/AHA stage 1 hypertension, 181 792 of 321 584 (56.5%) participants had a 10-year CVD risk score of 10% or higher and thus would qualify for antihypertensive medication (Table 1). The new BP threshold showed the greatest increase in prevalence of hypertension in the youngest age group (aged 18 to 25 years) and resulted in slightly greater increases in prevalence among those living in rural compared with urban areas (146.4% vs 130.0%) and those in the poorest compared with the richest households (160.5% vs 119.3%) (Table 2).
Table 1. Prevalence of Blood Pressure Thresholds and Cardiovascular Disease Risk Among Participants Aged 30 to 74 Years in the District-Level Household Survey-4 (DLHS4) and the Annual Health Survey (AHS) in Indiaa.
| Variable | Prevalence, No. (% [95% CI]) |
|---|---|
| Normal BP (<120/80 mm Hg) | 254 272 (31.9 [31.5-32.3]) |
| Elevated BP (120-129/<80 mm Hg) | 79 535 (10.0 [9.8-10.2]) |
| Stage 1 HTN (130-139/80-89 mm Hg) | 321 584 (40.3 [39.9-40.7]) |
| 10-y CVD risk ≥10%b | 181 792 (56.5 [56.2-56.9]) |
| Stage 2 HTN (≥140/90 mm Hg) | 142 149 (17.8 [17.5-18.1]) |
Abbreviations: BP, blood pressure; CVD, cardiovascular disease; HTN, hypertension.
Among 1 094 754 adults aged 30 to 74 years, 797 540 had nonmissing values for the variables needed to calculate the office-based Framingham risk score (blood glucose, systolic BP, height and weight, age, sex, and smoking status). All numbers shown in Table 1 are calculated among these 797 540 adults.
We had no data on previous or current cardiovascular disease events. These participants were thus not excluded from the Framingham risk calculation.
Table 2. Comparison of Age-Standardized Prevalence of Hypertension in India Among 1 387 680 Adults Aged 18 Years and Older.
| Variable | Prevalence (95% CI)a | Relative Increase in Prevalence | |
|---|---|---|---|
| JNC7 Guidelinesb | ACC/AHA Guidelinesc | ||
| Age, y | |||
| 18-25 | 12.51 (12.17-12.86) | 40.19 (39.60-40.78) | 221.26 |
| 26-35 | 17.18 (16.84-17.52) | 48.95 (48.43-49.46) | 184.92 |
| 36-45 | 24.97 (24.58-25.36) | 58.17 (57.68-58.66) | 132.96 |
| 46-55 | 32.96 (32.52-33.40) | 64.19 (63.70-64.69) | 94.75 |
| 56-65 | 39.82 (39.30-40.34) | 67.56 (67.03-68.08) | 69.66 |
| >65 | 45.22 (44.60-45.83) | 69.32 (68.73-69.91) | 53.30 |
| Educational attainment | |||
| <Primary school | 22.77 (22.39-23.16) | 52.07 (51.51-52.63) | 128.68 |
| Primary school | 20.87 (20.45-21.30) | 51.32 (50.71-51.93) | 145.90 |
| Middle school | 20.19 (19.79-20.59) | 51.02 (50.45-51.58) | 152.70 |
| Secondary school | 21.96 (21.59-22.33) | 53.15 (52.66-53.65) | 142.03 |
| High school | 20.05 (19.59-20.52) | 51.27 (50.67-51.88) | 155.71 |
| >High school | 23.42 (22.82-24.04) | 56.42 (55.77-57.06) | 140.91 |
| Sex | |||
| Male | 24.15 (23.78-24.52) | 58.26 (57.77-58.76) | 141.24 |
| Female | 19.67 (19.39-19.96) | 47.19 (46.76-47.63) | 139.91 |
| Residence | |||
| Rural | 20.43 (20.05-20.80) | 50.34 (49.77-50.91) | 146.40 |
| Urban | 24.69 (24.24-25.15) | 56.78 (56.22-57.34) | 129.97 |
| Household wealth quintiled | |||
| 1 | 18.24 (17.68-18.82) | 47.52 (46.64-48.40) | 160.53 |
| 2 | 19.27 (18.87-19.68) | 49.10 (48.48-49.72) | 154.80 |
| 3 | 21.60 (21.24-21.97) | 51.91 (51.40-52.42) | 140.32 |
| 4 | 25.00 (24.67-25.33) | 56.48 (56.08-56.88) | 125.92 |
| 5 | 27.61 (27.13-28.10) | 60.56 (60.08-61.03) | 119.34 |
| Regione | |||
| Central | 19.30 (18.47-20.16) | 51.91 (50.69-53.14) | 168.96 |
| East | 19.70 (19.16-20.25) | 47.69 (46.79-48.59) | 142.08 |
| North | 24.73 (24.04-25.42) | 56.81 (55.85-57.76) | 129.72 |
| Northeast | 19.54 (18.55-20.56) | 50.39 (49.06-51.72) | 157.88 |
| South | 24.16 (23.82-24.49) | 53.82 (53.44-54.21) | 122.76 |
| West | 24.71 (24.13-25.31) | 55.99 (55.39-56.59) | 126.59 |
Abbreviations: ACC/AHA, American College of Cardiology/American Heart Association; JNC7, Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure.
The prevalence was weighted to the Global Burden of Disease 2013 population structure for India.
JNC7 guidelines for blood pressure (BP) threshold: systolic BP ≥140 mm Hg or diastolic BP ≥90 mm Hg.
ACC/AHA guidelines for BP threshold: systolic BP ≥130 mm Hg or diastolic BP ≥80 mm Hg.
Calculated using a principal component analysis (PCA) of data on household ownership of 12 assets (radio, TV, computer, phone, fridge, bike, scooter, car, washing machine, sewing machine, house, and land) and 5 key housing characteristics (water supply, type of toilet and whether it is shared, cooking fuel, housing material, and source of lighting). The first component in the PCA was extracted separately for urban and rural areas, and this variable was divided into quintiles (separately for rural and urban areas) on the basis of distribution in the national data set.
Central region included Chhattisgarh, Madhya Pradesh, Uttarakhand, and Uttar Pradesh; East region, Bihar, Jharkhand, Odisha, and West Bengal; North region, Chandigarh, NCT of Delhi, Haryana, Himachal Pradesh, Punjab, and Rajasthan; Northeast region, Assam, Arunachal Pradesh, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim, and Tripura; South region, Andaman and Nicobar, Andhra Pradesh, Karnataka, Kerala, Puducherry, Tamil Nadu, and Telangana; West region, Daman and Diu, Goa, and Maharashtra.
Discussion
The lowered BP threshold in the new ACC/AHA guidelines resulted in a 140% relative increase in the hypertension prevalence in India. This increase was 3 times higher than the 43% relative increase reported in the United States.5 The prevalence reported in our analysis is likely an underestimate, given that the DLHS4 and the AHS did not collect information on antihypertensive medication use; thus, this study considered those individuals who achieved BP control with medication to not have hypertension.
Such an increase in the hypertension prevalence in India is likely to have significant implications for the Indian health system. Greater increases among younger patients and those from rural and poorest households may exacerbate the existing access-to-care issues in these high-risk subgroups. Hypertension treatment and control rates are already very low in India.6 The current health system, beset with an irregular supply of drugs and high load of patients, is unlikely to have the capacity to absorb such a significant surge in new patients. In our view, adoption of the new ACC/AHA guidelines in India is not advised. Instead, measures to strengthen the health system to manage existing cases as well as primary prevention efforts that target high dietary salt intake, low fruit and vegetable intake, excessive alcohol intake, physical inactivity, tobacco use, and air pollution should be encouraged.
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