UK: Life expectancy on HIV treatment improving, shows importance of prompt diagnosis and treatment

Michael Carter
Published: 12 October 2011

The life expectancy of patients receiving antiretroviral therapy in the UK improved significantly between 1996 and 2008, research published in the British Medical Journal shows. Patients who initiated HIV therapy when their CD4 cell count was in the region of 350 cells/mm3 had an average life expectancy of approximately 75 years.

However, starting HIV therapy with a CD4 cell count below 200 cells/mm3 was associated with a poorer prognosis, highlighting the importance of improved HIV testing and the prompt initiation of therapy.

“Life expectancy is strongly related to the CD4 count at which individuals start treatment,” write the investigators from the UK Collaborative HIV Cohort (UK CHIC). “This highlights the need to identify people infected with HIV early in the course of their infection, before substantial CD4 loss has occurred.”

Results also showed that, overall, the average life-expectancy of patients with HIV was about 13 years lower than that for the general UK population. However, all the average life expectancy figures reported by the researchers necessarily include patients who started treatment late. This group of patients are known to have a worse prognosis.

HIV is now considered a chronic, manageable condition, and with the right treatment and care the prognosis of many patients is excellent.  Although several studies have examined mortality rates in the era of effective HIV therapy, few have examined how long patients with HIV can now expect to live.

“Estimates of life expectancy are important to individuals who want to plan their lives better, to service providers, and to policy makers,” explain the investigators. They therefore used data collected between 1996 and 2008 to estimate the life expectancy of patients who started HIV therapy when their CD4 cell count was below 350 cells/mm3, the current threshold for starting antiretroviral treatment in the UK.

The life expectancy of patients with HIV was compared with the life expectancy of the general UK population, and the investigators also calculated the impact of late initiation of HIV therapy on prognosis.

A total of 17,661 individuals aged 20 and above were included in the study. Most of the patients were men (75%), white (58%), and their median age was 37 years. Overall, 42% of patients started HIV treatment late – defined as a CD4 cell count below 200 cells/mm3.

Patients were followed for a median of 5 years, and during 91,203 person years of follow-up a total of 1248 (7%) of individuals died. The overall mortality rate was 13.7 per 1000 person years. However, this fell from 28.8 per 1000 person years in 1996-99 to 9.5 per 1000 years between 2006-08.  Improvements in HIV treatment in care over the period largely account for this fall in the mortality rate.

The investigators calculated that a 20-year-old receiving HIV therapy in 1996-99 would live on average a further 30 years. This life expectancy increased to 46 years in the period 2006-08.

Life expectancy for a 35-year-old was an additional 20 years of life in 1996-99, and 31 years in the period 2006-08.

However, prognosis differed by gender, and was significantly better for women than men. Overall, life expectancy for a 20-year-old woman was an additional 50 years compared to 40 years for men.

HIV-positive patients had a significantly shorter life expectancy than individuals in the general population. A HIV-negative 20-year-old woman would be expected to survive until she was 82 years old and an HIV-negative man until he was 78.

“Compared with the same sex in the general UK population, for patients undergoing treatment for HIV infection, life expectancy at age 20 was 18.3 years less for men and 11.4 years less for women,” write the investigators.

They note “the prevalence of smoking, drug misuse, and alcoholism are all higher among people with HIV, which leads to increased deaths from cardiovascular disease, cancer, liver disease, suicide, overdose and injury.”

But further analysis showed that starting HIV treatment promptly significantly improved prognosis – which approached normal levels for patients who initiated therapy at a level indicated by current guidelines.

Patients who started therapy with a CD4 cell count between 200 and 350 cells/mm3 had an average life expectancy of 75 years, but this fell to 61 years for individuals who initiated therapy when their CD4 cell count was between 199 and 100 cells/mm3 and to 58 years for those who started treatment with a CD4 cell count below 100 cells/mm3.

 “Patients should start antiretroviral therapy once their CD4 cell count has fallen below 350 cells/mm3,” emphasise the investigators.

“Life expectancy among people with HIV has considerably improved in the UK between 1996 and 2008, and we should expect further improvements for patients starting antiretroviral therapy now with improved drugs and new guidelines recommending earlier treatment,” conclude the authors. “The clear impact of low CD4 cell count on life expectancy implies that it is particularly important to diagnose HIV infection at an early stage.”

Reference

May M et al. Impact of late diagnosis and treatment on life expectancy in people with HIV-1: UK Collaborative HIV Cohort (UK CHIC) study. BMJ 343, doi: 10.1136/bmj.d6016, 2011 (click here for the open access article).