Impact of Overweight on Renal Prognosis in Malignant Hypertension Patients With Thrombotic Microangiopathy

Abstract

Objective: Overweight and obesity is a risk factor for hypertension. Malignant hypertension (MHT) is the most severe form of hypertension, and thrombotic microangiopathy (TMA), one of its complications, has been linked to significant renal outcomes. However, the impact of overweight and obesity on renal prognosis in MHT patients with TMA is not well understood.

Methods: This was a prospective cohort enrolled 288 MHT patients with renal TMA from 2008 to 2023. The clinical and histopathological characteristics were recorded based on body mass index (BMI, < 25 and ≥ 25 kg/m²). The outcome was the incidence of kidney failure. The associations of BMI with kidney failure were examined in logistic regression models.

Results: Among 288 patients, 180 (62.5%) progressed to kidney failure, including 113 (68.5%) patients with BMI < 25 kg/m². Participants with obesity had higher levels of hemoglobin, estimated glomerular filtration rate and C3, but lower levels of serum creatinine and IgA nephropathy. BMI ≥ 25 kg/m² was associated with a better outcome of kidney failure in MHT patients with TMA (odd ratios [ORs]: 0.49 [95% confidence interval (CI): 0.27-0.91], p = 0.025). Male, uric acid, onion skin lesions, and global sclerosis ratio were correlated with higher risk of kidney failure; serum albumin and treatment with renin-angiotensin system blockers were related to lower risk of kidney failure.

Conclusions: In MHT patients with renal TMA, normal-weight rather than overweight was found to associate with a worse renal prognosis. Management efforts for MHT may be directed toward controlling body weight within a reasonable range for patients.

Keywords: kidney failure; malignant hypertension; overweight and obesity; renal biopsy; thrombotic microangiopathy.

FIGURE 1

Study flow.

FIGURE 2

BMI in male and female according to age. There is a positive linear relationship between 5th and 50th percentiles of BMI and age.

FIGURE 3

Representative light and electron microscopic findings of MHT patients with TMA. (a) Diffuse capillary loop wrinkling (red arrowheads) (PASM), 400×. (b) Marked intimal thickening of renal arterioles (red arrowheads) (PAS), 400×. (c) Arteriolar endothelial cell swelling, vessel wall thickening, and luminal occlusion with an “onion‐peel” appearance (red arrowheads) (PAS), 400×. (d) Electronic micrograph showed swelling of endothelial cells, capillary loop wrinkling, prominent subendothelial widening with flocculent material underneath, and new base membrane formation, leading to narrowing of capillary lumen (red arrowheads), 5000×. PASM, periodic acid–silver methenamine; PAS, periodic acid‐Schiff.