Over half of middle-aged HIV-positive patients in a large French cohort had poor
lower-limb strength, French investigators report in the online edition of AIDS.
They warn that this could mean the patients have a higher
risk of falls and recommend that assessments of lower-limb strength should be
carried out as part of routine HIV care.
Problems with balance and a deterioration of muscle strength
in the lower limbs (locomotor performance) are associated with ageing. Many
patients with HIV are now living into older age, and the diseases of ageing are
an increasingly important cause of illness and death in these individuals.
Research conducted in 2002 showed that up to 30% of
HIV-positive individuals had problems with muscle strength or balance.
Investigators from the French Agency for AIDS and Hepatitis Research (ANRS) CO3 Aquitaine Cohort
wished to gain a better understanding of locomotor performance in HIV-positive
patients in the modern treatment era.
They therefore designed a cross-sectional (or 'snap-shot')
study involving 324 patients who received care between 2007 and 2009.
Locomotor function was assessed using six validated
- An assessment of overall balance.
- Distance walked in six minutes at an accelerated
- Time to stand up from an armchair, walk three
metres, turn around, walk back to chair and sit down.
- Reach test.
- Static balance test.
- Five-times sit-to-stand test, an assessment of the
amount of time needed to stand up from a sitting position five times. This
assesses lower-limb strength.
The patients had a median age of 48, and 80% were men. They had
been living with HIV for a long time, and the median period since diagnosis was
almost 13 years. Consistent with this, 83% of patients were taking HIV therapy
and their median CD4 cell count was 520 cells/mm3.
Over half (53%) of individuals had a poor
five-times-sit-to-stand result. “The poor…performance was considerably higher
in our sample than the expected frequency in the general population,” comment
In addition, 24% of patients performed poorly on the walking
assessment, 11% had poorer than expected reach, and 10% had impaired balance.
Of the 172 patients with poor sit-to-stand results, 90 also
had poor result in at least one of the other assessments.
“Eighty-four percent of patients with poor six-minute walk
performance also had poor performance in the [five-times sit-to-stand] test,”
note the investigators.
Surprisingly, poor performance in the sit-to-stand
assessment was more common in younger patients. Results showed that 64% of
individuals under 50 performed poorly in this assessment compared to only 36%
of patients aged over 50. This difference was highly significant (p <
Given the high prevalence of poor performance in the
sit-to-stand assessment, the investigators restricted their statistical
analysis to the factors associated with this measure of lower limb strength.
Their first analysis showed that poorer performance
was associated with a range of risk factors, including: younger age (p <
0.0001), female sex (p < 0.01), injecting drug use (p < 0.01), hepatitis
C co-infection (p = 0.02), smoking (p < 0.01), a lower body mass index (p =
0.01), longer duration of infection with HIV (p < 0.0001), and therapy with
a 'd-drug' (ddI, d4t or ddC) (p < 0.001).
However, their final multivariate model, which controlled for
potential confounders, showed that only body mass index (p < 0.001) and
longer duration of infection with HIV (p < 0.001) were associated with poor lower-limb strength.
The effect of body mass index differed according to age. A
low body mass index was associated with poor performance in younger patients.
However, the opposite was true for older patients. Nevertheless, the
investigators believe that in both older and younger patients the underlying
reason was low muscle mass in the legs and buttocks.
Each year of infection with HIV increased the risk of poor
performance by 8%.
There was some suggestion that HIV therapy that included a d-drug was also associated with poor lower-limb strength, but this fell short
of statistical significance. Nevertheless, the investigators believe that this
finding “may warrant further exploration.”
“Given the high frequency of poor [five-times sit-to-stand] performance...we
recommend to perform [this] test in standard care,” write the authors, who
conclude with a call for longitudinal studies “to asses the evolution of
locomotor performance and the incidence of falls and their impact on fractures in the HIV-infected