Approximately 4.2 million over 50s are now living with HIV

Persuasive new data showing the ageing of the global HIV epidemic have been published in the online edition of AIDS. Using UNAIDS prevalence figures, investigators estimated that 4.2 million people aged 50 years or older were living with HIV in 2013. Prevalence among older people has more than doubled since 1995. Comparison with alternative data sources suggested that the UNAIDS figure was generally reliable.

“The number of people living with HIV aged 50 years and older is increasing,” comment the authors. “This trend is evident in the most recent UNAIDS estimates and is confirmed in national household survey data.”

There are number of possible explanations for the ageing of the HIV-positive population, especially the success of antiretroviral therapy and a high rate of new infections among older people.

Glossary

trend

In everyday language, a general movement upwards or downwards (e.g. every year there are more HIV infections). When discussing statistics, a trend often describes an apparent difference between results that is not statistically significant. 

sample size

A study has adequate statistical power if it can reliably detect a clinically important difference (i.e. between two treatments) if a difference actually exists. If a study is under-powered, there are not enough people taking part and the study may not tell us whether one treatment is better than the other.

sample

Studies aim to give information that will be applicable to a large group of people (e.g. adults with diagnosed HIV in the UK). Because it is impractical to conduct a study with such a large group, only a sub-group (a sample) takes part in a study. This isn’t a problem as long as the characteristics of the sample are similar to those of the wider group (e.g. in terms of age, gender, CD4 count and years since diagnosis).

An accurate understanding of the extent of the epidemic among the over 50s is needed so that appropriate medical services can be planned. This is especially important because living with HIV has been associated with an increased risk of diseases associated with old age.

Investigators from UNAIDS therefore analysed their own prevalence data to estimate the total number of older people living with HIV in 2013. They also examined long-term trends in HIV infections among older people and used national household surveys to see if their estimates were accurate.

The UNAIDS data showed that an estimated 4.2 million people aged 50 and older were living with HIV in 2013. The region with the largest number of older HIV-positive patients was sub-Saharan Africa (2.5 million people).

There was a steady increase in the number of people living with HIV aged 50 and older between 1995 and 2013, with the total number increasing more than two-fold between these years.

Since 1995, prevalence increased steadily in all five-year age groups aged over 50 years. Prevalence more than doubled in the 50-54 group, increased by a third in the 55-59 group and by a quarter in the 60-64 group.

Household surveys were generally in agreement with the UNAIDS estimates. Among men aged 50-54 years, estimated prevalence was approximately 10% lower than that revealed in the UNAIDS survey, with prevalence 27% lower in the 55-59 group. However, the investigators acknowledge this latter comparison was not robust because of a small sample size. For women, household surveys placed prevalence to within 2-10% of that suggested by the UNAIDS estimate. Four countries had household surveys for both men and women, and their results had prevalence within 10-15% of that suggested by UNAIDS for persons aged under 60.  

UNAIDS data and household surveys were in agreement that there had been sharp increases in the number of older people living with HIV in recent years.

The authors believe their findings have three important implications: (1) services need to expand to address the often complex needs of people living with HIV; (2) more attention needs to be given to HIV prevention for the over 50s; (3) more needs to be done to collect accurate data about the epidemic in older people and to understand the impact of HIV on these individuals.

References

Mahy M et al. Increasing trends in HIV prevalence among people aged 50 years and older: evidence from estimates and survey data. AIDS 28, online edition. DOI: 10/1097/QAD.0000000000000479, 2014.