Is measurement of blood pressure worthwhile in the diabetic eye clinic?

The UK Prospective Diabetic Study has confirmed the importance of blood pressure (BP) as a major risk factor for diabetic retinopathy (DR). We wanted to investigate whether measuring the BP in the diabetic eye clinic could identify new hypertensive patients and monitor control in existing ones.

We compared BP in patients attending the diabetic eye clinic with home blood pressure measurement (HBPM) and ambulatory BP measurement (ABPM). In all, 106 patients attending a diabetic eye clinic were selected at random from clinic attendees. BP measurement (on an Omron 705 CP) was performed in the eye clinic and also compared to HBPM three times per day with an Omron 705 CP machine, and was compared to diabetic clinic measurements. In addition, 11 randomly chosen patients had 24 h ABPM to validate the above techniques.

In all, 106 patients (70 male and 36 female) were recruited for the study, of which 71 were known to be hypertensive on antihypertensive medication. Of the total, 75 patients (70.8%) had BP > 140/85 in the eye clinic, of which 51 (68%) were known to be hypertensive on treatment and this was confirmed in 46 (90%) on HBPM. A total of, 24 patients (22.6%) were newly diagnosed as hypertensive in the eye clinic, which was confirmed by HBPM in 22 patients (92%). The mean BP of the measurements performed in the eye clinic was significantly higher than that carried out in the diabetic clinic (P < 0.01). Tropicamide 1% and phenylephrine 2.5% eye drop instillation had no effect on BP. In 11 randomly chosen patients, 24 h ABPM validated both diabetic eye clinic and home BP measurements.

Attendance at the diabetic eye clinic is an important chance to detect both new patients with systemic hypertension and those with inadequate BP control. Ophthalmologists should be encouraged to measure BP in their diabetic patients attending diabetic eye clinics, as it is an important risk factor for DR. On the basis of our findings, good BP control is a goal yet to be achieved in diabetic patients with retinopathy.