Only 1 in 15 urine dipstick tests showing proteinuria in the primary care setting are followed up with albuminuria quantification testing, according to investigators.
These findings expose a broad gap in screening for chronic kidney disease (CKD), which is especially concerning since newer kidney-protecting agents are more effective when prescribed earlier in the disease course, reported lead author Yunwen Xu, PhD, of Johns Hopkins Bloomberg School of Public Health, Baltimore, and colleagues.
“Evidence-based prescription of renin–angiotensin system inhibitors, glucagon-like peptide-1 receptor (GLP-1) agonists, sodium-glucose cotransporter-2 (SGLT2) inhibitors, and nonsteroidal mineralocorticoid receptor antagonists (nsMRAs) relies on the level of albuminuria,” the investigators wrote in Annals of Internal Medicine
“Although urine albumin-creatinine ratio (ACR) is the most accurate method for quantifying albuminuria, dipstick urinalysis tests are inexpensive and are often used as an initial screening test, with guidelines recommending follow-up ACR testing if the protein dipstick test result is abnormal.”
Despite this guidance, real-world follow-up rates have been unknown, prompting the present study. Real-world data show a low follow-up rate. Xu and colleagues analyzed data from 1 million patients in 33 health systems who underwent urine dipstick testing in a primary care setting.
Across this population, 13% of patients had proteinuria, but only 6.7% underwent follow-up albuminuria quantification testing within the next year. ACR was the most common method (86%).
Likelihood of follow-up increased slightly with the level of proteinuria detected; however, absolute differences were marginal, with a 3+ result yielding a follow-up rate of just 8%, compared with 7.3% for a 2+ result and 6.3% for a 1+ result. When albuminuria quantification tests were conducted, 1+, 2+, and 3+ dipstick results were associated with albuminuria rates of 36.3%, 53.0%, and 64.9%, respectively.
Patients with diabetes had the highest follow-up rate, at 16.6%, vs 3.8% for those without diabetes.
Reasons for Low Follow-up Unclear
The dataset did not include information about reasons for ordering urinalyses, whether primary care providers knew about the abnormal dipstick tests, or awareness of guideline recommendations.
“I think they know it should be done,” said principal investigator Alexander R. Chang, MD, associate professor in the department of nephrology and population health sciences at Geisinger, Danville, Pennsylvania.
He suggested that real-time awareness issues, especially within EHR systems, could explain the low follow-up rates. Blood test abnormalities are often flagged in red in EHRs, he said in an interview, but urine dipstick results typically remain in plain black and white.
“So, then it sort of requires that extra cognitive step to kind of look at that [result], and say, okay, that is pretty abnormal; I should do something about that,” he said.
Neil S. Skolnik, MD, a primary care physician at Jefferson Health, Abington, Pennsylvania, was surprised by the findings. “If you get a urinalysis and there’s protein, normally you follow up,” Skolnik said in an interview. “I have a feeling that there’s something we’re not seeing here about what’s going on. It is hard to imagine that in only 1 out of 15 times that proteinuria is identified, is there any follow-up. I really don’t have a good explanation.”
Renee Marie Betancourt, MD, associate professor and vice chair of diversity, equity, and inclusion in the Department of Family Medicine and Community Health at the University of Pennsylvania Perelman School of Medicine, Philadelphia, said it is hard to draw conclusions from the available data, but agreed that low visibility of results could be partially to blame.
“The chart doesn’t tell me [a urine dipstick result] is abnormal,” Betancourt said in an interview. “The chart just reports it, agnostic of normal or abnormal.”
Beyond issues with visibility, Betancourt described how primary care physicians are often so flooded with other concerns that a positive dipstick test can become a low priority, particularly among patients with CKD, who typically have other health issues.
“I oftentimes spend the majority of my visit on the patient’s concerns, and sometimes, beyond their concerns, I have concerns, and [a urine dipstick result] might not make it to the top of the list,” she said.
EHR-Based Interventions Might Help Improve Follow-up
Chang suggested that improved visibility of dipstick results could help, or possibly EHR-integrated clinical decision tools.
Betancourt and her colleagues at Penn Medicine are actively working on such a solution. Their EHR-based intervention is aimed at identifying and managing patients with CKD. The present design, slated for pilot testing at one or two primary care clinics beginning in January 2025, depends upon estimated glomerular filtration rate (eGFR) to flag CKD patients, with ACR testing recommended yearly to predict disease progression.
Although urine dipstick findings are not currently a part of this software pathway, the findings from the present study might influence future strategy.
“I’m going to take this to our collaborators and ask about opportunities to…encourage providers to be more active with dipsticks,” Betancourt said.
Newer Medications Are Effective, but Prescribing Challenges Remain
Ideally, CKD screening improvements will unlock a greater goal: prescribing kidney-protecting medications to patients who need them — as soon as they need them.
Here might lie the real knowledge gap among experienced primary care physicians, Chang suggested. “In the past, there wasn’t quite as much that you could do about having proteinuria,” he said. “But now we have lots more medications…it’s not just tracking that they have a bad prognostic factor. [Proteinuria is] actually something that we can act upon.”
Who exactly should be prescribing these kidney-protecting medications, however, remains contested, as agents like GLP-1 agonists and SGLT2 inhibitors yield benefits across specialties, including nephrology, cardiology, and endocrinology.
“Everyone’s going to have to work together,” Chang said. “You can’t really put it all on the [primary care physician] to quarterback everything.”
And, regardless of who throws the ball, a touchdown is not guaranteed.
Betancourt called out the high cost of these newer drugs and described how some of her patients, already facing multiple health inequities, are left without.
“I have patients who cannot fill these medications because the copay is too high,” she said. “Just last week I received a message from a patient who stopped taking his SGLT2 inhibitor because the cost was too high…it was over $300 per month.”
This study was supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health. The authors’ conflict-of-interest disclosures are available in the original paper. Drs Skolnik and Betancourt reported no conflicts of interest.
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