Urinalysis should be routine in patients with VTE

30 January 2012

MedWire News: US research shows that a “surprisingly high” proportion of patients with venous thromboembolism (VTE) have proteinuria and nephrotic syndrome (NS).

Furthermore, a lack of comprehensive, quantitative urine testing suggests that the prevalence of NS may actually be higher than the 2.5% that the researchers observed.

Naing Htike and colleagues from Lankenau Medical Center in Wynnewood, Pennsylvania explain that VTE is a well-known complication of NS.

However, it is less clear whether VTE, namely deep vein thrombosis (DVT) and pulmonary embolism (PE), represents an early manifestation of undiagnosed NS or chronic kidney disease.

To investigate, Htike and team reviewed the electronic medical records of 316 patients (median age 73 years, 61% women), admitted to a single community teaching hospital with new-onset, radiographically confirmed VTE.

The researchers found that urinalysis was performed in 198 (63%) patients whilst they were in hospital, and in a further 83 (26%) patients at a later date.

Proteinuria was identified in 154 (54%) of the patients who had a urinalysis, but only 29 (19%) patients with proteinuria subsequently had a formal evaluation of urine protein excretion, either by 24-hour urine protein collection or by spot protein to creatinine ratio.

Of these, eight (28%) had NS, defined as having at least 3.5 g proteinuria in 24 hours or a urine protein to creatinine ratio exceeding 3.5. The cause of NS was chronic kidney disease in three patients, hematologic malignancies in two patients, and diabetic nephropathy in two patients. There was no documented cause in the remaining two patients.

The fact that 11% of the study population did not have urine testing and only 9% of the total population had a quantification of their proteinuria makes it “impossible to know the true prevalence of NS in this cohort,” remark Htike and co-authors in the American Journal of Medical Sciences.

“Nevertheless, we uncovered NS in 2.5% (8 of 316 patients) of the cohort, which would vastly exceed even the most liberal estimates of the prevalence of NS in the United States,” they add.

Given the unexpectedly high prevalence of proteinuria and NS, the researchers recommend that urinalysis “should be part of the routine evaluation of a patient with VTE.”

MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2012

Am J Med Sci 2012; 343: 124–126