medwireNews: Obesity is as prevalent in people with type 1 diabetes as in the general US population and the age-adjusted chronic kidney disease (CKD) rate is higher than in people with type 2 diabetes, report researchers.
Elizabeth Selvin (Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA) and study co-authors observe that their findings from a US population are in line with those from other countries.
“The trends for increasing rates of obesity may signal a setback in the progress of improving health in this vulnerable population,” they write in The Journal of Clinical Endocrinology & Metabolism.
The team reviewed data from 4060 adults with type 1 diabetes and 135,458 with type 2 diabetes identified in the records of the Geisinger Health System in Pennsylvania between 2004 and 2018.
“Historically, people with [type 1 diabetes] have been thought to have lower rates of obesity than the general population,” say the researchers.
However, they found that the prevalence of obesity in people with type 1 diabetes rose from 32.6% to 36.8% during the study period, and was in line with rates in the US population, as assessed in 47,611 NHANES participants.
The obesity rate was higher in people with type 2 diabetes, at 58.1% in 2004 and 61.6% in 2018.
Chronic kidney disease (CKD), defined as a low estimated glomerular filtration rate (eGFR; ≤60 mL/min per 1.73 m2), remained fairly stable over time in people with type 1 diabetes, at 17.5% and 16.1% in 2004 and 2018, respectively. The rate in 2004 was higher than the 5.7% prevalence in the general population but lower than the rate in people with type 2 diabetes, of 26.6%.
The researchers note that this fits with the general belief that CKD is more common in people with type 2 diabetes than those with type 1 diabetes; however, they stress that “most studies have not adjusted for age.”
They say: “Older age is a major risk factor for CKD, and the population of adults with [type 2 diabetes] is much older than the population of adults with [type 1 diabetes].”
Indeed, in this study, people with type 1 diabetes were considerably younger than those with type 2 diabetes, at a median of 39 versus 62 years, and when the team adjusted for age, sex, and race, the prevalence of CKD was highest in people with type 1 diabetes, at around 20% compared with approximately 10% in those with type 2 diabetes.
This finding “has implications for long-term health,” say the researchers.
“With increased survival in the population of patients with [type 1 diabetes], it is likely that many patients will progress to end-stage kidney disease and will need kidney replacement therapy during their lifetime.”
The team also found that having obesity increased the likelihood of having low eGFR, by a significant 52% in people with type 1 diabetes and a smaller but still significant 29% in those with type 2 diabetes after accounting for age, sex, and race.
Selvin and colleagues suggest the smaller impact of obesity in people with type 2 diabetes could relate to them having more CKD risk factors, such as older age, than those with type 1 diabetes, “so obesity may have relatively less effect on the risk for CKD.”
Further adjustment for hypertension rendered the association between obesity and CKD nonsignificant in people with type 1 diabetes, but attenuated it only slightly in those with type 2 diabetes.
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J Clin Endocrinol Metab 2022; doi:10.1210/clinem/dgab927