Background/Purpose:

To study the effect of renal disease on survival and life expectancy of patients with systemic lupus erythematosus (SLE).

Methods:

Patients who fulfilled >=4 ACR criteria for SLE who were prospectively followed in our unit from 1995 to 2011 were studied. The cumulative survival rate was calculated using Kaplan Miere’s plot.  The standardized mortality ratios (SMR) (adjusted for age and sex) compared to the general population within the same period of time was worked out.  The effect of renal involvement, different histological classes, renal damage and end stage renal failure on survival of SLE was also evaluated by the Cox proportional hazard models, with adjustment for age, sex and use of various immunosuppressive drugs.

Results:

694 patients were studied (92% women; mean age of onset of SLE 32.9±13.4 years).  368 (53%) had evidence of renal disease according to the ACR definition (persistent proteinuria of >=0.5g/day; cellular casts or histological evidence).  285 (77%) patients had undergone renal biopsy for at least 1 time.  The distribution of histological classes (ISN/RPS) was: class I (1%), class II (6%), class III (19%), class III+V (10%), class IV (47%), class V (16%) and others (1%).  The mean follow-up time was 9.6±7.3 years, 79 (11%) had renal damage as assessed by the SLE damage index (SDI) and 24 (3%) patients developed end stage renal failure (ESRF).  The cumulative 5, 10 and 15 year survival of patients with renal involvement was 92.3%, 88.8% and 84.3%, respectively (significantly lower than that of patients without renal disease [97.0%, 93.7% and 91.6%, respectively; log rank test p=0.004]).  Cox regression demonstrated the age and sex adjusted hazard ratio (HR) of mortality in patients with renal disease and renal damage compared with those without renal was 2.23 [1.29-3.85] (p=0.004) and 3.59 [2.20-5.87] (p<0.001), respectively.  The corresponding HR ratio for mortality in patients who developed ESRF was 9.20 [4.92-17.2] (p<0.001).  Patients with proliferative types of lupus nephritis (class III, IV±V) had significantly increased mortality (adjusted HR 2.28[1.22-4.24]; p=0.01).  In contrast, pure membranous lupus nephropathy was not associated with increased mortality (adjusted HR 1.09 [0.38-3.14]; p=0.88).  The age and sex adjusted SMRs of all SLE patients, SLE patients with renal disease, proliferative nephritis, pure membranous nephropathy, renal damage and renal failure compared to the general population were 7.3[5.7-9.3], 9.1[6.7-12.0], 9.8[6.5-14.1], 6.2[2.0-14.4], 13.9[9.1-20.4] and 63.1[33.6-108], respectively. All patients with proliferative or membranous lupus nephritis were treated with glucocorticoids, and the proportion of patients who had ever received other immunosuppressive agents in combination was: azathioprine (89%), cyclophosphamide (51%), MMF (50%), cyclosporin A (31%), tacrolimus (38%) and hydroxychloroquine (68%).  Adjustment for the use of immunosuppressive regimens in the Cox regression models above did not materially affect the overall hazard ratios for mortality.

Conclusion:

The presence of renal disease, in particular proliferative types of nephritis causing renal function impairment, significantly increases the mortality risk of patients with SLE.

 

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/effect-of-renal-disease-on-survival-of-patients-with-systemic-lupus-erythematosus-a-prospective-cohort-study-of-694-patients/