Many Indian Heart Patients Have Hidden High Blood Pressure, Study Finds

A new study from India found that many patients being treated for high blood pressure still have dangerous levels — but only when blood pressure is checked at home. The study looked at nearly 1,600 patients across 18 medical centers in 12 Indian states. Researchers measured blood pressure both at the doctor's office and at home over seven days. The results showed that relying only on clinic readings gave a much rosier picture than the truth.

High blood pressure, also called hypertension, is very common in India. About one in four adults has it, and even among those being treated with medicine, only about half had it under control. Doctors have known that a single reading at a clinic can be misleading. Until now, there was not much large-scale data from India combining both clinic and home readings.

The GRAND Study enrolled 1,920 patients between the ages of 20 and 70 who were already taking blood pressure medicine. After two rounds of clinic readings, patients were given a digital blood pressure monitor to use at home. They measured their blood pressure twice in the morning and twice in the evening for seven days straight. This gave researchers a much fuller picture of each patient's true blood pressure.

After gathering all the data, researchers sorted patients into four groups. About 55.9% had well-controlled blood pressure both at the clinic and at home. About 5.1% showed high readings at the clinic but normal readings at home — this is called 'white-coat' hypertension, which happens because some people get nervous at the doctor's office. About 21.8% had the opposite problem: their clinic readings looked fine, but their home readings were too high, a condition called 'masked' hypertension.

The most important finding was the big gap between clinic readings and the full picture. Using only clinic blood pressure, about 78 out of every 100 patients appeared to have their condition under control. But when home readings were added, that number dropped to only about 56 out of 100. That means roughly 1 in 5 patients was incorrectly thought to be 'fine' when their blood pressure was actually still too high at home.

Masked hypertension is especially worrying because there are no warning signs during a doctor's visit. Patients with this condition may feel like everything is under control, but their hearts and blood vessels are still under stress. Researchers noted that about one in five patients in this study had masked hypertension. Asian populations, including people in India, tend to have higher rates of this condition than people in Western countries.

The study also found that about 42% of patients had diabetes, and nearly 48% had high cholesterol alongside their high blood pressure. These conditions together raise the risk of heart attacks and strokes even further. When blood pressure is not truly under control, the danger for these patients becomes even greater. That is why researchers say getting an accurate picture of blood pressure is so important.

Despite some limitations — such as most patients being from cities and private hospitals — researchers believe their findings send a clear message. Checking blood pressure only at a clinic is not enough. They are calling for better guidelines in India that encourage patients to monitor their blood pressure at home regularly, so that fewer people slip through the cracks with undetected high blood pressure.