Neural dysfunction and retinopathy in persons with type 1 diabetes

Reduced microvascular reactivity in patients with diabetic neuropathy

BACKGROUND

Neurogenic regulation is involved in the development of microcirculation response to local heating. We suggest that microvascular reactivity can be used to estimate the severity of diabetic polyneuropathy (DPN).

OBJECTIVE

To evaluate the prospects for using the parameters of skin microvascular reactivity to determine the severity of DPN.

METHODS

26 patients with diabetes mellitus were included in the study (patients with retinopathy (n = 15), and without retinopathy (n = 11)). The severity of DPN was assessed using Michigan Neuropathy Screening Instrument (MNSI) and Norfolk QOL-DN (NQOLDN). Skin microcirculation was measured by laser Doppler flowmetry with local heating test.

RESULTS

There were revealed moderate negative correlations between microvascular reactivity and the severity of DPN (for MNSI (Rs = -0.430), for NQOLDN (Rs = -0.396)). In patients with retinopathy, correlations were stronger than in the general group (for MNSI (Rs = -0.770) and NQOLDN (Rs = -0.636)). No such correlations were found in patients without retinopathy.

CONCLUSION

Correlation of the microvascular reactivity and DPN was revealed in patients with registered structural disorders in microvessels (retinopathy). The lack of such correlation in patients without retinopathy may be explained by the intact compensatory mechanisms of microvessels without severe disorders.

Risk factors for prevalent diabetic retinopathy and proliferative diabetic retinopathy in type 1 diabetes

PURPOSE

Age at diagnosis of type 1 diabetes (DM1) has been implied as an important factor associated with the development of the microvascular complications. Our aim was to identify factors associated with prevalent diabetic retinopathy (DR) and proliferative diabetic retinopathy (PDR) in DM1 people with early and late-onset.

METHODS

We reviewed medical records from all DM1 people from the reference area of a tertiary center (about 340,000 persons). Univariate and multivariate logistic regression were used to assess the relationship between potential risk factors (sociodemographic, diabetes-related, co-morbidities, and laboratory parameters) and prevalent DR/PDR. We performed an analysis comparing patients diagnosed before (early-onset) and after (late-onset) 18 years of age.

RESULTS

We included 140 patients in early-onset DM1 group and 169 in late-onset DM1 group. Longer duration of diabetes and HbA1c remained associated with prevalent DR in both groups after adjusting for potential risk factors. Nephropathy was associated with prevalent DR in the late-onset group but not in the early-onset group. Peripheral neuropathy remained associated with prevalent PDR when modeled together in the multivariate model. High BMI demonstrated a significative association with PDR in early but not in the late-onset DM1 group.

CONCLUSIONS

Although previous reports suggest that age at DM1 diagnosis may have a role in DR prevalence, the risk factors for DR in early and late-onset DM1 were similar for both groups. Duration of disease and lifelong metabolic control were the major predictors for DR in both groups. Nephropathy was associated with DR in patients with late-onset disease. Neuropathy was associated with PDR occurrence in both groups. BMI was associated with PDR early-onset DM1 group.