By Liz Highleyman

Fat accumulation at the back of the neck -- known as cervical lipomatosis or "buffalo hump" -- was among the first recognized manifestations of lipodystrophy (body fat changes) reported after protease inhibitors came into widespread use in the late 1990s.

Since that time, however, more attention has focused on visceral or abdominal fat accumulation, fat loss in the face and limbs (lipoatrophy), and metabolic complications including elevated blood lipids and insulin resistance.

As reported in the January 2007 issue of HIV Medicine, Spanish researchers assessed the prevalence of cervical lipomatosis in HIV positive individuals on HAART and factors associated with its development. In this multicenter case-control study, HIV-infected patients with lipomatosis were paired with HIV positive control subjects without the condition, matched for age, sex, and body mass index.

Results

• Cervical lipomatosis was reported in 80 patients (1.8%) out of a cohort of 4214 individuals on HAART followed at 10 Spanish hospitals.

• In a univariate analysis, cervical lipomatosis was associated with:

- longer duration of HIV infection;
- waist-to-hip ratio;
- lipoatrophy;
- fat gain in the breasts;
- elevated total cholesterol;
- lower HDL "good" cholesterol;
- high triglyceride;
- treatment with saquinavir (Invirase/Fortovase), indinavir (Crixivan), efavirenz (Sustiva), d4T (Zerit), or tenofovir (Viread).

• In a multivariate analysis, however, buffalo hump remained significantly associated only with:

- 6 duration of exposure to d4T (odds ratio 5.82 for each 6-month increase in drug exposure; P = 0.0073);
- presence of lipoatrophy (odds ratio 8.04; P = 0.00001).

Conclusion

In conclusion, the authors wrote, "Although lipodystrophy is very frequent among HIV-infected patients on HAART, cervical lipomatosis is an uncommon type of fat redistribution in this population, and in our cohort it was related to time of exposure to stavudine and lipoatrophy."

Previous studies have produced rates of buffalo hump ranging as high as 13%. The current data may indicate that the prevalence of the condition may be decreasing as d4T and other NRTIs linked to lipodystrophy are less frequently used in antiretroviral regimens. The current study did not support a link between cervical lipomatosis and use of protease inhibitors.

Hosp. Virgen de la Victoria, Malaga, Spain; Hosp. General, Valencia, Spain; Hosp. Principe de Asturias, Alcalá de Henares, Spain; Hosp. de Valme, Seville, Spain; Hosp. Clínico San Carlos, Madrid, Spain; Hosp. Reina Sofía, Cordoba, Spain; Virgen Macarena, Seville, Spain; Hosp. General de Asturias, Oviedo, Spain; Hosp. Costa del Sol, Marbella, Spain; Hosp. Infanta Cristina, Badajoz, Spain.

02/16/07

Reference
R Palacios, M J Galindo, J A Arranz, and others. Cervical lipomatosis in HIV-infected patients: a case-control study. HIV Medicine 8(1): 17. January 2007.