Renal Effects of High-Dose Versus Low-Dose Lisinopril in Patients With Diabetic Nephropathy

Background The present study was conducted to assess the renal effects of high dose versus low dose lisinopril in patients with diabetic nephropathy. Methodology A prospective observational study was conducted at the Khyber Teaching Hospital, Peshawar, Khyber Pakhtunkhwa, Pakistan, between July 1, 2019, to January 1, 2020. Patients were divided into two groups. Group A patients were administered a low dose (5 mg per day) of Lisinopril and group B were administered a higher dose of therapy (20 mg/day) for three months. At the end of the study, baseline renal functions, electrolytes, and status of microalbuminuria were compared with follow-up values. The primary outcome was to assess the change in microalbuminuria levels in patients at baseline, one month, and three months of therapy. Results A total of 72 patients were included in group A (low dose) and 72 patients were enrolled in group B (high dose). The mean ages of group A and group B were 56.3 ± 12.9 years and 53.48 ± 12.2 years, respectively. The majority of the patients in the groups were male. At baseline, the mean microalbuminuria levels in the two groups were not significantly different however, at three months post treatment, the levels were significantly much lower in high dose patients as compared to patients who were on low dose lisinopril (146.06 ± 23.89 vs. 184.69 ± 26.27; p < 0.0001). The three-month urea levels were significantly lower in group A as compared to group B (38.91 ± 7.07 vs. 43.26 ± 3.02; p = 0.008). Three-month creatinine and potassium levels were not significantly different between the groups (p = 0.7 and 0.12, respectively).  Conclusion Our study revealed that even though group B (high dose lisinopril) had significantly reduced microalbuminuria, the urea levels were found to be higher in this cohort of patients as compared to group A patients on low-dose lisinopril. Moreover, the majority of the patients in group B reported significant improvements in blood pressure control as compared to group A, which indicated that a high dose of lisinopril is more effective in patients with diabetic nephropathy than a low dose of lisinopril. The levels of creatinine after three months of treatment did not differ significantly. Further randomized trials are warranted in order to ascertain the effectiveness of high dose of lisinopril in patients with diabetic nephropathy.