Renal disease in systemic sclerosis with normal serum creatinine

Assessment of kidney involvement in systemic sclerosis: From scleroderma renal crisis to subclinical renal vasculopathy

The spectrum of kidney involvement in systemic sclerosis (SSc) includes scleroderma renal crisis, widely recognized as the most severe renal-vascular complication, but also several forms of chronic renal vasculopathy and reduced renal function are complications of scleroderma. Scleroderma renal crisis, myeloperoxidase-antineutrophil cytoplasmic antibody associated glomerulonephritis, penicillamine-associated renal disease, abnormal urinalysis, alteration of vascular endothelial markers, scleroderma associated-vasculopathy with abnormal renal resistance indices and cardiorenal syndromes type 5 were also reported in SSc patients. A frequent form of renal involvement in SSc patients is a subclinical renal vasculopathy, characterized by vascular damage and normal renal function. Indeed, asymptomatic renal changes, expressed by increase of intrarenal stiffness, are often non-progressive in SSc patients but can lead to a reduction in renal functional reserve. The purpose of this review is to provide an assessment of kidney involvement in SSc, from SRC to subclinical renal vasculopathy.

Estimated glomerular filtration rate and renal resistive index as possible predictive markers of mortality in systemic sclerosis

OBJECTIVE

Subclinical nephropathy is underestimated in systemic sclerosis (SSc). Study aim is to evaluate the role of renal resistance indices (RRI) and estimated glomerular filtration rate (eGFR) assessed by Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) as predictive markers of mortality during 10 years of follow-up in SSc patients.

METHODS

181 SSc patients (60 years, 152 females) were enrolled. At baseline, the GFR was estimated in 181 SSc patients and RRI was measured in 122 SSc patients. During a follow-up of 10 years we recorded the main complications of disease, date and causes of death.

RESULTS

eGFR shows a linear negative correlation with RRI. RRI showed a correlation with systolic pulmonary artery pressure (sPAP). Overall survival is lower in SSc patients with eGFR<60 ml/min and RRI ≥0.70 than in SSc patients with eGFR≥60 ml/min (p<0.0001) and with RRI<0.70 (p<0.01) both for mortality due to SSc and all causes. In multivariate analysis, eGFR<60 ml/min [HR 6.429, 95%CI (1.006-41.08), p<0.05] and forced vital capacity (FVC) [HR 0.954, 95%CI (0.911-1), p<0.05] are predictive markers of mortality due to SSc, while eGFR [HR 3.617, 95%CI (1.370-9.554), p<0.01], RRI [HR 0.210, 95% CI (0.068-0.649), p<0.01], age [HR 1.062, 95%CI (1.023-1.103), p<0.01], FVC [HR 0.967, 95%CI (0.946-0.989), p<0.01] and disease activity index (DAI) [HR 1.663, 95%CI (1.262-2.191), p<0.0001] are predictive markers of mortality due to all causes.

CONCLUSION

We demonstrate that eGFR is a predictive marker of mortality due to SSc and to all causes, conversely RRI is predictive marker of mortality due to all causes.

Renal dysfunction in systemic sclerosis beyond scleroderma renal crisis

Research regarding renal involvement in SSc has almost exclusively focused on scleroderma renal crisis (SRC). There are relatively limited data regarding renal impairment in SSc beyond SRC. We performed an electronic search using the key words systemic sclerosis or scleroderma combined with each of the following: renal dysfunction, kidney, glomerular filtration rate (GFR), proteinuria and hematuria. We searched for reports relevant to renal dysfunction in SSc beyond SRC. In 796 SSc patients recruited in five studies. 251 (31.5%) had GFR < 90 ml/min whereas 155(19.5%) patients had GFR < 60 ml/min. Most data indicate that the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula should be considered as the most suitable tool for assessing renal function in SSc pts, since it provides similar results to measured GFR. These data indicate that renal dysfunction in SSc in not uncommon and therefore patients with SSc should have their renal function assessed by GFR estimation on a regular basis.

Estimated glomerular filtration rate is a marker of mortality in the European Scleroderma Trials and Research Group (EUSTAR) database

OBJECTIVES

Study aim was to evaluate estimated glomerular filtration rate (eGFR), its association with clinical disease and its predictive ability with mortality in systemic sclerosis (SSc) patients from the European Scleroderma Trials and Research Group (EUSTAR) database.

METHODS

SSc patients from the EUSTAR database with available items for calculation of eGFR at baseline visit and with a second follow-up visit were included. A cut-off of 60 ml/min was chosen for all SSc patients and 30 ml/min for scleroderma renal crisis (SRC). Cox regression and competing risk analysis were performed to evaluate the role of eGFR as predictive factor of mortality.

RESULTS

3650 SSc patients were included. Mean serum level of creatinine and eGFR were 0.8 mg/dl (IQR 0.6-0.9) and 86.6 ± 23.7 ml/min. The eGFR was significantly lower in patients with pulmonary hypertension. Overall survival (OS) was significantly reduced in SSc patients with eGFR <60 ml/min respect to patients with eGFR ≥ 60 ml/min [OS at five years 0.763 (CI 95%: 0.700-0.814) vs 0.903 (CI 95%: 0.883-0.919 p< 0.001)]. In multivariable analysis, OS was associate with male gender (p< 0.01), systolic pulmonary arterial pressure (sPAP) (p< 0.001) and eGFR (p< 0.001). Cumulative incidence of deaths due to SSc was associate with increased sPAP (p< 0.001) and reduced eGFR (p< 0.05). OS at five years of 53 SRC patients was not significantly different in SSc patients with eGFR > 30 ml/min or eGFR < 30 ml/min.

CONCLUSION

eGFR represents a predictive risk factor of overall survival in SSc. The eGFR is not a risk factor for death in SRC.

Renal Parenchymal Thickness in Patients with Systemic Sclerosis Is Related to Intrarenal Hemodynamic Variables and Raynaud Renal Phenomenon

Objective.

Renal involvement in systemic sclerosis (SSc) ranges from urinary abnormalities, reduction of glomerular filtration rate, and high renal resistive index, to scleroderma renal crisis. Intrarenal resistance indices are considered markers of renal SSc-associated vasculopathy. The aim of this study is to evaluate renal morphological variables, such as renal length, parenchymal thickness, atrophy index, and renal sinus in patients with SSc and to correlate it with renal function and hemodynamic variables.

Methods.

There were 92 patients with SSc and 40 healthy controls (HC) enrolled in this study. Doppler and renal ultrasound (US) including renal length, parenchymal thickness, atrophy index, renal sinus, and intrarenal resistive index were measured in patients with SSc and HC.

Results.

Renal US showed significant differences between HC and patients with SSc. The renal length (mm; 106.7 ± 5.1 vs 102.3 ± 8.4) and renal sinus (70.7 ± 7.9 vs 65.3 ± 7.7 mm) were significantly (p = 0.001) higher in HC than patients with SSc. The parenchymal thickness was significantly (p = 0.004) higher in HC than patients with SSc (18 ± 3.1 vs 16.3 ± 2.5 mm). Pulsatility index, resistive index, and systolic/diastolic ratio were significantly (p < 0.0001) lower in HC than patients with SSc. The renal length was significantly (p = 0.004) higher in diffuse cutaneous SSc (105 ± 8.4) than in limited cutaneous SSc (99.5 ± 7.5).

Conclusion.

In SSc, kidney involvement is subclinical and is related to vascular injury, Raynaud phenomenon, and chronic hypoxia that can modify renal morphology. Serum creatinine is a poor marker of renal damage, and renal US could be a useful tool — together with Doppler — to evaluate renal involvement in a systemic and chronic disease such as SSc.

Influence of antiphospholipid antibody positivity on glomerular filtration rate markers in a group of systemic sclerosis patients - a 24-month observation

Aim of the study

The aim of the study was the assessment of changes in the glomerular filtration rate (GFR) during long-term observation in a group of systemic sclerosis (SSc) patients with and without chronic antiphospholipid (aPL) antibody positivity.

Material and methods

The observation comprised 50 patients – 23 with diffuse cutaneous SSc – dcSSc and 27 limited cutaneous SSc – lcSSc. After 24 months we assessed 27 patients (9 died, 14 lost follow up); 24 patients (88%) were treated chronically with angiotensin-converting-enzyme inhibitors (ACEIs). Patients were investigated for the presence of aPL: to cardiolipin and to β2 glycoprotein I in IgM and IgG classes. Serum levels of creatinine (S-Cr), cystatin C and creatinine clearance values were determined in all patients. According to the presence of a significant level of at least one of aPL antibodies, pts were divided into groups: group I aPL positive: 14 patients, group II aPL negative – 13 patients.

Results

We did not find significant differences in S-Cr, cystatin C levels and creatinine clearance before and after 24 months of observation between both groups. In follow up observations, the presence of anti-centromere antibodies was significantly more frequent in the aPL positive, as compared to the aPL negative group (p = 0.01). In follow up observations, the level of anticardiolipin antibodies in IgG class was significantly higher in dcSSc compared to lcSSc patients (p = 0.02).

Conclusions

In long-term observation chronic positivity for aPL antibodies does not significantly decrease the GFR in patients with SSc treated with ACEIs.

Angiogenic and angiostatic factors in renal scleroderma-associated vasculopathy

BACKGROUND

The angiogenesis in systemic sclerosis (SSc) is impaired. An imbalance of pro-angiogenic factors and angiogenesis inhibitors has been implicated in the progression of peripheral microvascular damage, defective vascular repair and fibrosis. Intrarenal resistance index are considered markers of renal vasculopathy. The aim of the study is to evaluate angiogenic and angiostatic factors (VEGF and endostatin) in SSc patients and to correlate with intrarenal hemodynamic parameters.

METHODS

91 SSc patients were enrolled in this study. Serum VEGF and endostatin levels were determined. All patients underwent a renal Doppler ultrasound RESULTS: A significant positive correlation was observed between endostatin and renal Doppler parameters (p<0.0001). A negative correlation was observed between serum levels of endostatin and eGFR (p<0.01). In SSc patients with high resistive index, serum levels of endostatin were significantly (p<0.01) higher than in SSc patients with normal resistive index. The serum levels of endostatin significantly increased with progression of nailfold videocapillaroscopy damage (p<0.01) and were significantly (p<0.05) higher in SSc patients with digital ulcers than in SSc patients without digital ulcers.

CONCLUSION

This is the first study that assess in SSc patients intrarenal hemodynamic parameters and endostatin. In SSc patients, endostatin represents a marker of renal scleroderma-associated vasculopathy.

Arterial hypertension treated with angiotensin converting enzyme inhibitors and glucocorticoids are independent risk factors associated with decreased glomerular filtration rate in systemic sclerosis

The aim of this study was to estimate prevalence and severity of renal insufficiency in systemic sclerosis (SSc) and to assess risk factors associated with reduced glomerular filtration rate (GFR) in SSc patients. Seventy-three consecutive patients with SSc (67 women and 6 men), mean age 56.2 years, mean disease duration 6.7 years, were included in this cross-sectional study. GFR was measured by creatinine clearance (CCr) in all patients, as well as 24-h proteinuria. We assessed frequency and severity of renal insufficiency in our patients with SSc and estimated the association of renal insufficiency with age, disease duration, subtype of the disease, earlier diagnosed arterial hypertension, and medications for which we assumed to affect renal function-cytostatics, nonsteroidal anti-inflammatory drugs, glucocorticoids, ACE inhibitors, diuretics, and calcium channel blockers (CCB). Fifty-six out of 73 patients with SSc (76.7%) had reduced GFR (CCr lower than 90 ml/min), compared to 17/73 (23.3%) of patients with normal renal function. Mild renal insufficiency was noticed in 28/73 (38.4%), moderate in 21/73 (28.8%) and severe renal insufficiency in 5/73 (6.8%). End-stage renal disease (CCr < 15 ml/min) was found in 2/73 (2.7%) of patients. Using the univariate general linear statistical model, we have found that previously diagnosed arterial hypertension and treatment with glucocorticoids are independent risk factors for reduced GFR. On the other hand, age, disease duration, disease form, as well as antibodies (anticentromere antibodies-ACA and anti-topoisomerase I antibodies-ATA) were excluded as independent risk factors. Patients with SSc and arterial hypertension treated with CCB had significantly higher mean CCr than patients treated with diuretics (90.4 vs 53.5 ml/min, p = 0.03), or patients treated with ACE inhibitors (90.4 vs 41.7 ml/min, p = 0.001). Decreased GFR is common in SSc. Most of patients have mild or moderate renal insufficiency. Previously diagnosed arterial hypertension, especially when treated with ACE inhibitors or diuretics, and glucocorticoids are independent risk factors associated with reduced GFR in SSc. These medications should be therefore used with caution in SSc patients.

Scleroderma renal crisis and renal involvement in systemic sclerosis

Scleroderma renal crisis (SRC) is a rare, potentially life-threatening complication that affects 2-15% of patients with systemic sclerosis (SSc, also known as scleroderma). SRC typically presents in patients with early, rapidly progressive, diffuse cutaneous SSc within the first 3-5 years after the onset of a non-Raynaud sign or symptom. SRC is characterized by an acute, usually symptomatic increase in blood pressure, a rise in serum creatinine levels, oliguria and thrombotic microangiopathy in about 50% of patients. The prognosis of SRC substantially improved in the 1980s with the introduction of angiotensin-converting-enzyme inhibitors for rapid blood pressure control, with additional antihypertensive agents as required. However, the survival of patients with SRC can still be improved. Current patient survival is 70-82% at 1 year, but decreases to 50-60% at 5 years despite dialysis support. Patients with SRC who show no signs of renal functional recovery despite timely blood pressure control are candidates for transplantation. In this Review, we discuss progress made in the identification and proactive management of patients at risk of SRC and make recommendations aimed at optimizing management for those who progress to chronic kidney failure.

Renal disease in scleroderma: an update on evaluation, risk stratification, pathogenesis and management

PURPOSE OF REVIEW

Renal disease remains an important cause of morbidity and mortality in scleroderma. The spectrum of renal complications in systemic sclerosis includes scleroderma renal crisis (SRC), normotensive renal crisis, antineutrophil cytoplasmic antibodies-associated glomerulonephritis, penacillamine-associated renal disease, and reduced renal functional reserves manifested by proteinuria, microalbuminuria, or isolated reduction in glomerular filtration rate. The purpose of this review is to provide a concise and up-to-date review of the evaluation, risk stratification, pathogenesis, and management of scleroderma-associated renal disease.

RECENT FINDINGS

Although SRC survival has significantly improved, mortality of this complication remains high outside of specialized centers. Recent data demonstrate strong associations between anti-RNA polymerase III antibodies and SRC. Subclinical renal impairment affects approximately 50% of scleroderma patients and may be associated with other vascular manifestations. Subclinical renal involvement rarely progresses to end-stage renal failure; however, recent studies suggest it may predict mortality in patients with other vasculopathic manifestations.

SUMMARY

Testing for anti-RNA polymerase III antibodies should be incorporated into clinical care to identify patients at high risk for SRC. Recommendations from European League Against Rheumatism (EULAR), EULAR Scleroderma Trials and Research, and the Scleroderma Clinical Trials Consortium confirm angiotensin-converting enzyme inhibitors as first-line therapy for SRC, and give recommendations for second-line agents.

Tc-99m diethylenetriamine pentaacetic acid (DTPA) renal function reserve estimation: is it a reliable predictive tool for assessment of preclinical renal involvement in scleroderma patients?

Prognosis of systemic sclerosis (SSc) depends on internal organ involvement. We assessed the value of renal function reserve (RFR) for the detection of preclinical nephropathy in scleroderma. Thirty SSc patients with normal serum creatinine and 30 healthy controls were included. Medsger disease severity score, glomerular filtration rate (GFR), and microalbuminuria were measured. Tc-99m DTPA was utilized for GFR measurement at baseline and after oral protein overload (stimulated GFR). RFR was calculated as the percentile increase of stimulated GFR. SSc patients had lower means of baseline GFR (P=0.001), stimulated GFR (P=0.004), RFR (P=0.046), and higher microalbuminuria (P=0.009) than controls. According to baseline GFR, SSc patients showed three categories-normal baseline GFR (n=12), hyperfiltration GFR (n=3), and reduced baseline GFR (n=15). In the former category, RFR was normal in 6/12 patients and abnormal in the remainders (50%). Hyperfiltration patients and those with reduced baseline GFR showed abnormal RFR. A statistically significant negative association was found between microalbuminuria versus stimulated GFR and RFR (r= -0.5, P=0.007 and r= -0.45, P=0.013, respectively). The majority of SSc patients with abnormal RFR had disease duration of ≥48 months (60% vs. 20%, P=0.008). All SSc patients with pulmonary hypertension had abnormal RFR, while reduced baseline GFR was noted in only 60%. A significant negative correlation was found between reduced baseline GFR and cumulative dose of corticosteroids in SSc patients (r= -0.4, P=0.022). RFR estimation could be a useful predictive marker for preclinical renal involvement in SSc patients so that early prophylactic measures and therapy modifications could be considered.

Renal manifestations in scleroderma: evidence for subclinical renal disease as a marker of vasculopathy

Scleroderma is a disease characterized by immune activation, vasculopathy, fibroblast stimulation, and connective tissue fibrosis. End-organ damage occurs due to progressive tissue fibrosis and vasculopathy. Markers of incipient vasculopathy have not been well studied in scleroderma. However, reduced renal functional reserve and proteinuria are common indicators of progressive vasculopathy in diabetic and hypertensive vasculopathy. Recent studies suggest a strong association between renal involvement and outcomes in scleroderma, with a threefold increased risk of mortality from pulmonary hypertension if renal insufficiency is present. We review the types of renal involvement seen in scleroderma and the data to support the use of renal parameters including proteinuria, glomerular filtration rate, and renal vascular dynamics measured with Doppler ultrasound to identify subclinical renal insufficiency. Further studies are warranted to investigate the use of renal parameters as prognostic indicators in scleroderma.