Prevalence of elevated C-reactive protein among newly diagnosed type 2 diabetes patients in Denmark: Results from the population-based DD2 study

Objectives: Levels of high-sensitivity C-reactive protein (CRP) are increased in patients with prevalent type 2 diabetes (T2D) and may predict coronary heart disease. There is limited knowledge of CRP levels among newly diagnosed T2D patients in the population-based setting. We determined the prevalence of elevated CRP in T2D patients included in the Danish DD2 study, and factors associated with such elevation.
Methods: Measurements of CRP were performed in the first 1,036 T2D patients included in the DD2 project, a large nationwide prospective research project enrolling new T2D patients from general practitioners and hospital specialist outpatient clinics. We calculated median value and interquartile range of CRP, and examined the number of T2D patients within tertiles of CRP values, and within clinically relevant cutoff points of CRP (<1.0, 1.0–2.99, 3.0-5.99, or >=6.0 mg/L). We also examined demographic, clinical, and lifestyle characteristics associated with elevated CRP.
Results: The distribution of CRP was right skewed, with a median value of 2.1 mg/L (inter-tertile range, 1.3 - 3.6 mg/L). 20.6% of patients had a CRP level of 3.0 - 5.99 mg/L and 19.6% had a CRP of >=6 mg/L. As compared to the 361 people with CRP values in the lowest tertile (<= 1.3 mg/L), those with CRP values in the highest tertile (>3.6 mg/L) were younger (median age 58 vs. 62 years, p<0.0001) and more likely to be female (52.7% vs 39.3%, prevalence ratio 1.34 (95% CI: 1.18-1.50)). Patients in the highest CPR tertile had substantially higher median values of BMI (34.4 vs. 28.7 kg/m2, p<0.001) and waist circumference (113 cm vs. 100 cm, p<0.001), and were less likely to do regular sports activities (30.8% vs. 46.3%, prevalence ratio 0.67 (95% CI 0.47-0.86). They also had a higher median HbA1C (7.2 vs. 6.6%, p<0.01), higher fasting blood glucose (7.26 vs. 6.82 mmol/L, p<0.0001), higher C-peptide (784 vs. 545, p<0.0001), and were more likely to be on insulin treatment (7.7% vs. 5.0%, prevalence ratio 1.54 (95% CI: 0.96-2.13). Blood pressure, lipids, and current smoking were similar between groups. Patients with high CRP had higher Charlson comorbidity index scores (score >=1 in 35.2% vs. 26.1%) and more previous cardiovascular disease (20.4% vs. 16.9%) and chronic pulmonary disease (12.4% vs. 6.6%). Nonetheless, fewer in the elevated CRP group were on statin therapy (58.9% vs. 69.3%).
Conclusions: Among newly diagnosed T2D patients in Denmark, 19.6% had CRP values of more than 6 mg/L. Patients in the highest CRP tertile were more likely to be female, obese, physically inactive, and comorbid, with worse blood glucose control compared to those with low CRP.