Elevated blood pressure in subjects with lipodystrophy
Simon Collins, HIV i-Base
The importance of elevated blood pressure (hypertension) and the relationship with lipodystrophy, which has not previously been researched, was addressed by Sattler and colleagues from University of Southern California.
This was a retrospective analysis from records of 42 consecutive people with diagnosed lipodystrophy who had been referred to a metabolic disorders clinic from March 1998 to August 1999.
For each symptomatic patient, blood pressure was assessed from six months prior to the time of initiation of a PI or NNRTI containing regimen (23±16 measurements over 21±11 months). 42 age- and sex-matched HIV-positive people using similar HAART but without diagnosed lipodystrophy and 13 HIV-negative people were used as control groups. Family history of hypertension was taken into account in the final analysis (higher in the cohort at 62% versus 36% for HIV-positive control).
Elevated blood pressure was defined as three or more readings in medical records showing diastolic blood pressure (DBP) >90mmHg or systolic values >140 mgHg. Mean values of the three highest readings over the study period were used to compare to the HIV-positive control group.
Lipodystrophy symptoms were present in the following percentage of the group: lipoatrophy 88% (peripheral limb 69%, facial 57%, buttocks 55%), accumulation 69% (abdominal 57%, buffalo hump 24%, multiple lipoma 7%, breast 7%) and metabolic 86% (fasting TG ?200mg/dl 33%, HDL ?35mg/dl 48%, total cholesterol ?200mg/dl 63%).
Although the HIV-positive control group were selected on the basis that they had no apparent lipodystrophy symptoms, baseline body measurements and blood lipid levels were similar to the study cohort.
However, the proportion of people with elevated BP was higher in the cohort (74%) than in the HIV-positive controls (48%). Diastolic PB increased in 71% versus 43% and systolic BP in 43% versus 21% respectively (p=0.02 for each).
There was a higher incidence of family history of hypertension in a first degree relative in the cohort compared to the HIV-positive control group (62% versus 36%) and when the data were controlled for this the difference in blood pressure between the two groups diminished, although the number of subjects with three elevated SBP or DBP results, the proportion of readings elevated, and mean of three highest DBP were all higher in the lipodystrophy group and this was statistically significant (P<0.05).
Waist-to-hip ratio (WHR) significantly correlated with SBP (p=0.01) and increased WHR occurred more frequently in patients with elevated blood pressure than those with normal blood pressure (34% versus 16%) although the actual number of patients involved was small. WHR correlated with SBP in the lipodystrophy cohort compared to HIV-negative controls. There was also a high tendency for correlation between fasting triglycerides and SBP in HIV-positive patients in either group.
Because the HIV-positive control group actually had a similar rate of clinical (but undiagnosed) lipodystrophy to the lipodystrophy cohort there was not really a non-lipodystrophy HIV-positive control. However in both HIV-positive groups the proportion of people with elevated SBP was greater than the proportion with elevated DBP and isolated elevation of SBP is an independent risk factor for cardiovascular complications.
Only one woman was included in the study so further studies are required in more representative cohorts in order to understand the relationship between blood pressure, HIV and lipodystrophy.
Non-pharmacologic interventions such as diet, exercise and reduced salt and alcohol intake were advocated for patients with more than three SBP readings 140-159 mmHg and drug therapy was used for higher levels or non-responsive cases.
The study provided supportive evidence that lipodystrophy can contribute to risk factors for hypertension and that as hypertension in itself is a risk factor for myocardial infarction, stroke, renal failure and peripheral arterial disease. The study also showed that is may be common for elevated levels to continue for extended periods (over two years).
Sattler FR, Qian D, Louie S et al – Elevated blood pressure in subjects with lipodystrophy. Journal of AIDS 2001 Oct 19;15(15):2001-10.