BP Still High With Lupus Nephritis in Remission

More than half of lupus nephritis (LN) patients in complete remission and with preserved renal function still have persistent hypertension, Malaysian researchers reported in a study published online in Clinical Rheumatology.

"The prevalence of hypertension [in] LN is high despite remission. Aggressive treatment is important to achieve early complete remission and to prevent relapses," concluded Syahrul Syazliana Shaharir, MD, and colleagues from the National University of Malaysia in Kuala Lumpur.

Arterial hypertension has been reported in as many as 74% of patients with systemic lupus erythematosus, and LN occurs in 75% of lupus patients. While hypertension contributes to accelerated atherosclerosis and premature cardiovascular disease, little is known of the operative pathophysiological mechanisms.

The Malaysian study aimed to determine hypertension prevalence in LN patients in complete remission. While hypertension correlates markedly with active LN, there is little data on hypertension in LN patients in remission.

Researchers undertook a cross-sectional study of 64 eligible LN patients at the university medical center's nephrology and SLE clinic. Hypertension was determined as blood pressure of at least 140/90 mm Hg on a minimum of two occasions in patients, and complete remission for at least 6 months. Since significant renal impairment is associated with hypertension, only LN patients with an estimated glomerular filtration rate (eGFR) of more than 60 mL/min/1.73m² were included.

Complete remission was defined as proteinuria of no more than 0.5 g/day or a urine protein-creatinine index of less than 0.05 g/mmol; urinary red cells of fewer than 5 red blood cells (high-power field); and no cellular casts in the urine.

Patients' mean creatinine was 65.2 (SD 15.2) mmol/L and their mean eGFR was 100.7 (SD 22.5) mL/kg/1.73 m². Mean age was 33.5 years (SD 8.7); mean disease duration was 8.4 years (SD 5.5). Of the 57 who had renal biopsies, proliferative LN was found in 84.2%, with 40.3% being class IV/V and 31.6% being class III/V according to the WHO 1995 Classification. Thirty-four (53.1%) were hypertensive.

Independent factors associated with hypertension (P<0.05) were: disease duration (odds ratio 1.06, 95% CI 0.91-1.24); longer duration interval to complete remission (OR 1.10, 95% CI 1.02-1.19); number or relapses (OR 2.53, 95% CI 1.01-6.3); and CyA use (OR 5.3, 95% CI 1.14-23.9).

The authors pointed out that corticosteroids are the mainstays of LN treatment but can promote hypertension through sodium and fluid retention. In this study, however, the maximum oral corticosteroid use (mg/d) did not relate to the development of hypertension (37.8, SD 13.1, versus 41.9, SD 15.6, P=0.3). Nor was either crescent or global sclerosis associated with persistent hypertension.

The investigators also found no relationships between hypertension and histological classes, nephrotic range proteinuria, BMI, or waist circumference.

Apart from renal involvement, they surmise that hypertension could arise from other causes such as endothelial dysfunction and SLE-related alterations in body composition, as well as the use of glucocorticoids and CyA. "Hypertension is a known side effect of effective treatment with CyA," the authors wrote. "It has a prominent effect on the blood vessels and leads to systemic vasoconstriction [particularly in the kidney], thus causing reduced glomerular filtration rate and sodium retention."

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