Associations of lipoprotein subclasses with risk of all-cause and cardiovascular disease mortality in individuals with type 2 diabetes: A prospective cohort study

AIM

Although lipoproteins are well-established risk factors for cardiovascular disease (CVD) mortality, conventional measurements failed to identify lipoprotein particle sizes. This study aimed to investigate associations of lipoprotein subclasses categorized by particle sizes with risk of all-cause and CVD mortality in individuals with type 2 diabetes.

METHODS

This study included 6575 individuals with type 2 diabetes from the UK Biobank. Concentrations of very low-, low-, intermediate- and high-density lipoprotein [very-low-density lipoprotein (VLDL), low-density lipoprotein (LDL), intermediate-density lipoprotein and high-density lipoprotein (HDL)] particles in 14 subclasses and lipid constituents within each subclass were measured by quantitative nuclear magnetic resonance. Multivariable-adjusted Cox proportional-hazard regression models were used to estimate the hazard ratio (HR) for per standard deviation increment of log-transformed lipoprotein subclasses with risk of mortality. All p-values were adjusted by the false discovery rate method.

RESULTS

During a median follow-up of 11.4 years, 943 deaths were documented, including 310 CVD deaths. Small HDL particles were inversely associated with CVD mortality, with HR (95% CI) of 0.78 (0.69, 0.87), whereas very large and large HDL particles were positively associated with CVD mortality with HR (95% CI) of 1.28 (1.12, 1.45) and 1.19 (1.05, 1.35), respectively. A similar pattern was observed for all-cause mortality [small HDL particle (HR, 95% CI): 0.79, 0.74-0.85; large HDL particle: 1.15, 1.07-1.24; very large HDL particle: 1.26, 1.17-1.36]. For VLDL and LDL, very small VLDL particle was positively, while medium LDL particle was inversely associated with all-cause mortality, but not associated with CVD mortality. The pattern of association with all-cause and CVD mortality for cholesterol and triglyceride within lipoprotein particles was similar to those for lipoprotein particles themselves.

CONCLUSIONS

The associations between lipoprotein particles, particularly HDL particles, with all-cause and CVD mortality among patients with type 2 diabetes were significantly varied by particle sizes, highlighting the importance of particle size as a lipoprotein metric in mortality risk discrimination.

[Role of electrocardiogram in predicting cardiac resynchronization therapy response]

OBJECTIVE

To explore the role of electrocardiogram(ECG)in predicting cardiac resynchronization therapy (CRT) response.

METHODS

This study retrospectively analyzed ECG of 92 CRT patients, who received CRT therapy from 2001 to 2013 in our center and were followed up for 6 months. The patients were divided into responder group (n=64) and non-responder group (n=28). The baseline and 6-month data including QRS width, heart rhythm and axis variation were analyzed. The definition of responder is left ventricular end systolic volume (LVESV) reduction ≥15% within 6 months after CRT. After CRT therapy, the ventricular activation was changed as left to right (frontal plane), posterior to anterior and axis changed in a clockwise direction. The change in more than two directions was defined as prominent axis change. Logistic analysis was performed to analyze the role of ECG in predicting CRT response.

RESULTS

(1) Baseline parameter comparison between the two groups: the proportion of female and LBBB is significantly higher (P<0.01; P=0.04), while the proportion of atrial fibrillation/flutter (Af/AF) is significantly lower (P<0.01) in responder group than in non-responder group. The pre-CRT average QRS duration is much wider in responder group than in non-responder group (P=0.01). (2) Comparison of follow-up with baseline results in two groups: NYHA heart function level, 6 minutes walking distance, QRS duration, LVEF, LVESV improved significantly (P<0.01) post-CRT in responder group. In non-responder group, the QRS duration and LVESV deteriorated significantly (P=0.02, P<0.01), while post-CRT NYHA heart function level improved significantly. In responder group, pre-CRT ECG axis of 53 patients (82.8%) pointed to left and 58 patients (90.6%) pointed to posterior; post-CRT ECG axis of 49 patients (76.6%) pointed to right and 30 patients (40.6%) pointed to anterior. In non-responder group, pre-CRT ECG axis of 25 patients (89.3%) pointed to left and 24 patients (85.7%) pointed to posterior; post-CRT ECG axis of 17 patients (60.7%) pointed to right and 12 patients (42.9%) pointed to anterior. Post-CRT, the proportion of ECG axis prominent change was significantly higher in responder than in non-responder group (62.5%(40/64) vs. 32.1%(9/28), P=0.007). (3)Predicting value: pre-CRT QRS width ≥140 ms (OR=4.97, 95% CI 1.53 to 16.13, P=0.008)and post-CRT prominent axis change (OR=5.1, 95% CI 1.67 to 15.5, P=0.004)were found to be independent predictors of CRT responders. Af/AF pre-CRT was associated with reduced CRT response (OR=0.25, 95% CI 0.08 to 0.80, P=0.02).

CONCLUSIONS

ECG may play a role in predicting CRT response. QRS width and Af/AF before CRT and ECG axis change post-CRT could be used to predict CRT response.

Inflammatory markers and risk of type 2 diabetes: a systematic review and meta-analysis

OBJECTIVE

There has been growing evidence that inflammatory markers play a role in the development of type 2 diabetes. We aimed to systematically review prospective studies on the associations of elevated levels of interleukin-6 (IL-6) and C-reactive protein (CRP) with increased risk of type 2 diabetes by conducting a meta-analysis.

RESEARCH DESIGN AND METHODS

A systematic search of the PubMed, EMBASE, ISI Web of Knowledge, and Cochrane Library databases up until 10 February 2012 was conducted to retrieve prospective studies matched to search terms. We used generalized least-squares trend estimation to assess dose-response relationships. The summary risk estimates were pooled using either fixed-effects or random-effects models to incorporate between-study variation.

RESULTS

The meta-analysis, including 10 prospective studies, with a total of 19,709 participants and 4,480 cases, detected a significant dose-response association of IL-6 levels with type 2 diabetes risk (relative risk [RR] 1.31 [95% CI 1.17-1.46]). For CRP, the meta-analysis involving 22 cohorts, with a total of 40,735 participants and 5,753 cases, showed that elevated CRP levels were significantly associated with increased risk of type 2 diabetes (1.26 [1.16-1.37]), with the absence of publication bias. Sensitivity and subgroup analyses further supported the associations.

CONCLUSIONS

This meta-analysis provides further evidence that elevated levels of IL-6 and CRP are significantly associated with increased risk of type 2 diabetes.