A recent cross-sectional study conducted by the National Health and Nutritional Examination Survey (NHANES) program has found that no significant variation has been noticed in the prevalence of diabetic kidney disease (DKD) pattern among US population from 1988 to 2014 but the prevalence of albuminuria has declined and reduced eGFR has increased.
DKD development and progress is usually signaled by the onset of albuminuria followed by a reduced eGFR. At least, this is how the trend has been over the last 20 years. However, there have been instances when GFR loss has preceded albuminuria in diabetic patients. In fact, sometimes only reduced eGFR, and complete absence of albuminuria, heralded the onset of DKD in patients.
Albuminuria is a condition when kidney fails to function properly and starts excreting a protein called albumin in the urine. In other words, it is urine albumin to creatinine ratio, whereas excess albumin to creatinine ratio in urine leads to kidney failures. On the other hand, GFR tells the volume of blood that is filtered by our kidney over a given period of time with value of 60 or high indicating normal kidney function and 15 or lower may mean kidney failure.
The purpose of the study was to investigate whether the trend, that has remained steady over the last two decades, has changed. More importantly, the researchers wanted to find out if diabetic management over time with blood sugar control, blood pressure control, and increased use of renin-angiotensin-aldosterone system (RAAS) inhibitors had any impact on the progress of DKD.
The study observed the trend in albuminuria and reduced eGFR in 6251 patients belonging to multi-ethnic backgrounds from 1988 to 2014. The study evaluated more advanced DKD manifestations including DKD screening, interventions and new treatments. The participants were tested via a questionnaire about their diabetes type, its diagnosis pattern, first and current administration pattern of insulin as well as medications taken during the process. During the study, younger adults from the non-Hispanic white background received more glucose-lowering medications, RAAS inhibitors and statins over time, as compared to older black and Mexican American, with no interference of age.
The researchers found that while the prevalence of diabetes among US adults did not change from 1988 to 2014, there has been a change in two major determinants of disease progression – albuminuria and eGFR. According to the study, the prevalence rate of albuminuria reduced among non-Hispanic whites and adults from 20.8% in 1998 to 15.9% in 2014.
When the researchers studied the eGFR pattern among the patients, they found its prevalence to have increased over the last two decades — 9.2% in 1988 to 14.1% in 2014. Though the study didn’t mention any factors that contributed to this increase, there are factors that generally contribute in the reduction of the eGFR such as age, medications and hypotension and prolonged duration of diabetes contributes to kidney damage.
The trend of age distribution of the US population with diabetes didn’t change in the study. This study has been an extension of the previous study conducted by the same researchers in 2008. Earlier, the researchers noticed an increase in reduced GFR in participants but no significant changes in albuminuria. This time around, the study was more in depth and included a variety of parameters such as subgroups, minorities, race/ethnicity, time interactions, significant age and older adults. The researchers concluded that improved diabetes interventions i.e., usage of prescribed diabetic therapies such as glucose-lowering medications, RAAS inhibitors, and statins, have resulted in lower albuminuria incidences among US adults with diabetes and diabetic kidney disease.
Over all the study was a huge achievement towards the persistence behavior of diabetic kidney failure disease cases over a specific period of time but still this study had some limitations. For instance, diabetes is not the only reason of kidney failure, there could be other factors contributing as well but no sufficient data was present to identified the real reason, also the participants with type 2 diabetes were at highest risk. One possibility could be the shifting in gathering the data for the serum creatinine, urine albumin and creatinine measurements over time.
Kidney is a cleaning factory that works by excreting waste fluids out of the body and maintain the body’s homeostasis between salt and solvent concentration. In the case of diabetic kidney failure, kidney filters fail to clean the bodily fluids and they start accumulating in the body. Diabetes is one of the leading causes of kidney failure among US population. According to the Centers for Disease Control and Prevention (CDC), in 2014, 20.1 million cases of diabetes have been diagnosed. According to United States Renal Data System 2007 report, 43.8% cases of renal failure are associated with diabetes and about 180,000 people ae living with renal failure in United States.