Relationship between retinopathy and renal abnormalities in black hypertensive patients

BACKGROUND: Complications of hypertension are particularly common in people of African descent but previous reports had suggested rarity of hypertensive retinopathy in black Africans. We evaluated retinal changes among Nigerian hypertensive patients and determined their relationship with renal function. METHODS: Consecutive Hypertensive patients who were ≥18 years were selected for the study. Socio-demographic characteristics, anthropometric parameters and blood pressure were measured. All patients had ophthalmoscopic examination and retinal changes were graded according to Keith-Wegener’s classification. Blood samples were taken for blood urea nitrogen, lipids and C-reactive protein; and urine was collected for creatinine and microalbuminuria. Serum creatinine was determined using modified Jaffe method and estimated glomerular filtration (eGFR) was calculated using MDRD equation: 186 × (Creatinine/88.4)(-1.154) × (Age)(-0.203) × (0.742 if female) × (1.210 if black). RESULTS: Of the 240 patients studied, 187 (78 %) had one form of retinopathy or the other. While 85 (35.4 %) patients had grade 1 retinopathy, 87 (36.3 %) had grade 2, 13 (5.4 %) had grade 3 and 2 (0.83 %) had grade 4 respectively. Comparison of patients with and without retinopathy showed that, the former were older (p = 0.001) and had longer duration of hypertension (p = 0.001). Similarly, hypertensive patients with retinopathy had higher total cholesterol and low density lipoprotein cholesterol (p = 0.017, p = 0.041 respectively). However, eGFR was lower in individuals with retinopathy (46.2 ml/min/1.73) than those with normal retinal (55.9 ml/min/1.73) findings, p = 0.019. Multi-variable adjusted odds ratios showed increased probability of retinopathy with age (odds ratio-1.08, p = 0.001) and body mass index (odds ratio-1.20, p = 0.013). CONCLUSIONS: Hypertensive retinopathy is a common clinical finding among hypertensive Nigerians and may occur pari passu with renal damage as consequences of long standing hypertension.