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Thursday, 5 September 2013

In Hypertensive Patients With Diabetes Low BMI is a Risk Factor for CVD: Research

New research reveals that low BMI is a risk factor for CVD in hypertensive patients with diabetes. The research was presented at the ESC Congress today by Dr Takanori Nagahiro from Japan. The findings provide evidence for an obesity paradox in hypertensive patients with glucose intolerance.

Dr Nagahiro said: "Obesity is a risk factor for cardiovascular disease (CVD) but several studies have reported that low body mass index (BMI, kg/m2) was associated with worse cardiovascular outcome compared to middle or higher BMI. This strange phenomenon is called the 'obesity paradox' and has been described in patients with stroke, heart failure, coronary artery disease and renal disease." 

He added: "The obesity paradox was reported in diabetic patients in 2012. Adults who were normal weight at the time of incident diabetes had higher mortality than adults who were overweight or obese.1 However, the relationship between obesity and cardiovascular events in patients with diabetes and hypertension is unknown." 

The current study assessed the relationship between BMI and cardiovascular events in patients with hypertension and glucose intolerance. The researchers used data from the Nagoya Heart Study, a randomised trial comparing the efficacies of valsartan and amlodipine among 1,105 hypertensive patients with glucose intolerance in Japan. Patients were enrolled from October 2004 to January 2009 and the median follow-up was 3.2 years. The CVD endpoint was a composite of acute myocardial infarction, stroke, admission due to heart failure, coronary revascularization, or sudden cardiac death. 

Patients were classified2 into four groups according to their baseline BMI: <23kg/m2 (n=283), 23 to 24.99kg/m2 (n=290), 25.00 to 27.49kg/m2 (n=277), and ≥27.50kg/m2 (n=255). Stratified analyses were performed according to these groups with the lowest BMI category as reference. 

The primary endpoint occurred in 42 patients (14.8%, 4.6/100 patient-years) in the lowest BMI category (the reference group), 24 patients (8.3%, 2.3/100 patient-years) in the BMI 23.00 to 24.99kg/m2 group (hazard ratio [HR] =0.48), 27 patients (9.7%, 2.8/100 patient-years) in the BMI 25.00 to 27.49kg/m2 group (HR=0.57), and 13 patients (5.1%, 1.5/100 patient-years) in the highest BMI category (HR=0.32). 

Dr Nagahiro said: "As BMI increased, CVD risk decreased among Japanese hypertensive patients with glucose intolerance. After adjustment for age, gender and smoking status, the lowest BMI group showed the highest CVD incidence and the highest BMI group had the lowest CVD incidence. CVD risk in the highest BMI group was less than one-third that of the lowest BMI group." 

The Kaplan-Meier curve shows the proportion of patients who reached the primary endpoint over time (see figure). The maximum follow-up period was 2,126 days (5.8 years). Dr Nagahiro said: "Our study shows that there is an obesity paradox in hypertensive patients with glucose intolerance. This may be because of the severity of diabetes mellitus in the lowest BMI group. Baseline HbA1c and disease duration is similar to other groups however the percentage of insulin therapy is higher than other groups. This background indicates that the severity of diabetes mellitus is different. The two middle BMI groups had similar CVD risk, probably because mild obesity needs more time to exert an adverse effect on the cardiovascular system." 

He concluded: "Hypertensive patients with glucose intolerance and a high BMI should lose weight and restore their BMI to normal range. The results of our study did not refute the fact that severe obesity is a CVD risk factor."

As one of the Type 2 diabetics with a low BMI to me this just goes to show the value of LCHF.



Anonymous said...

Interesting and recommended read

Lowcarb team member said...

Totally agree with your comment Graham.

T2s with a low BMI seem at greater risk of complications in general, and when they get them, they are harder to deal with - as I can testify. I think that probably means they are not T2s.

A senior diabetic nurse at the hospital recently commented to me that T2s often say to her that they have "the easier one T2" but she feels that this is not necessarily the case-particularly slim T2s with complications-probably as a result of being undiagnosed for longer.

No disrespect intended to T1's who have all my sympathy.


Galina L. said...

I will not be totally surprised if it would be recognized in a nearest future that it is healthy to be able to store fat easily, especially on extremities. There are numerous people who look like that they are unable to store fat anywhere but their middle-section , a lot of old folks like that. I guess, ones who can't store fat anywhere could have even more compromised health.

Lowcarb team member said...

Kath said...

"T2s with a low BMI seem at greater risk of complications in general, and when they get them, they are harder to deal with - as I can testify.

I do think Kath that our main problem is there is little if any helpful information aimed at the slim Type 2. We don't have the option of losing weight to improve our insulin resistance, that also means calorie reduction is out of the question.

As you can see from the text I highlighted the low BMI group had a higher percentage using insulin, which is not surprising if they were consuming a high calorie diet based on carbs.


Lowcarb team member said...

Re your comment above graham , no we don't have the option of losing weight to improve our insulin resistance but when I gained weight with glimepiride and then had to lose it my insulin resistance was vastly improved and the Dr’s were amazed. It was thought I would be able to reduce my meds gradually. I had to ditch them immediately or suffered sever hypos. Perhaps slim T2s should be made to gain weigh under supervision and then when they lose it {much easier for us than others} we might see a rapid loss and improvement in insulin resistance.

Perhaps its the actual process of losing weight rather than the weight itself -perhaps it kick-starts the metabolism in some way? Metformin works best for the overweight they say.