Decrease heart rate variability but preserve postural blood pressure change in type 2 diabetes with microalbuminuria.

BACKGROUND: This study compares the cardiovascular autonomic function in type 2 diabetes with and without microalbuminuria, in order to identify the possible links between early nephropathy and diabetic autonomic neuropathy (DAN). METHODS: Cardiovascular reflex tests were performed to determine the cardiovascular autonomic function. Thirty cases of type 2 diabetes with microalbuminuria were studied for evidence of DAN to compare with a normoalbuminuric group of 56 diabetic patients. RESULTS: There was an increased prevalence of autonomic dysfunction in patients with microalbuminuria (63.3% in the microalbuminuria group vs. 40.0% in the normoalbuminuric controls, p = 0.001). These patients had lower heart rate variability during single breathing tests (6.9 +/- 4.3 vs. 9.6 +/- 3.6 beats/minute, p = 0.005), during 6 consecutive breathings (5.8 +/- 3.6 vs. 8.2 +/- 3.3 beats/minute, p = 0.005), after standing up (12.2 +/- 4.6 vs. 15.0 +/- 5.2 beats/ minute, p = 0.012), and during the Valsalva maneuver (11.3 +/- 3.5 vs. 13.2 +/- 3.6 beats/minute, p = 0.022). The heart rate variability with these stresses was revealed to be less favorable in subjects with microalbuminuria. However, blood pressure (BP) changes from the sitting to standing position were not significantly different for systolic BP (11.5 +/- 10.7 vs. 10.7 +/- 7.8 mmHg, p = 0.741) and diastolic BP (5.2 +/- 4.4 vs. 5.9 +/- 4.0 mmHg, p = 0.451) between the 2 groups. CONCLUSION: Type 2 diabetic patients with microalbuminuria have diminished heart rate variability in response to deep breathing, change of position and the Valsalva maneuver, but they preserve BP response to postural change. Therefore, microalbuminuria seems to be associated with early DAN, but not with advanced DAN.

The role of insulin-like growth factor-1 and growth hormone in the mortality of patients with acromegaly after trans-sphenoidal surgery.

CONTEXT: Acromegaly is associated with a significant increase in mortality. With the development of new modalities of treatment, it has become important to identify prognostic factors relating to mortality. OBJECTIVE: This study aimed to determine the all-cause mortality of patients with acromegaly after trans-sphenoidal surgery, and assess the impact of biochemical markers on survival. DESIGN: Two hundred thirty-four patients were admitted to the Taipei Veterans General Hospital for acromegaly between 1979 and 2007. Of the 163 patients who underwent trans-sphenoidal surgery, 142 had data available for insulin-like growth factor-1 (IGF-1), and their survival status was analyzed. Serial data for fasting growth hormone (GH) and IGF-1 were collected. This study also used the last follow-up data for mortality analysis. The patients with acromegaly were grouped according to the last follow-up GH level (≤2 or >2 µg/L) and IGF-1 SD score (≤2 or >2). All-cause mortality was followed to the end of 2007 and compared to the general Taiwanese population by standardized mortality ratios. RESULTS: Serial GH and IGF-1 data revealed that the GH levels in the first 3 years after surgery were important predictors of mortality in acromegaly. However, there are insufficient IGF-1 data for deceased patients to determine the significance of a raised IGF-1 immediately following treatment. Comparison of crude death rates suggests that a fasting GH level of 2 µg/L and normalization of the IGF-1 level are appropriate targets. After subgroup analysis to assess the impact of discordant GH and IGF-1 levels on survival, the data showed that the elevated GH group had a trend toward a higher mortality than the elevated IGF-1 group. CONCLUSIONS: An elevated GH value in the first 3 years after surgery may be the best predictor of mortality. Thus, the follow-up of patients with acromegaly at relatively frequent intervals after trans-sphenoidal surgery should be routine.