Haiti study shows lab tests sometimes cost-effective for HIV, even in poorest countries

Only routine laboratory monitoring for asymptomatic anaemia was clinically beneficial and cost-effective when compared to symptom-driven testing in a study of HIV-positive patients in Haiti.

The retrospective study of a cohort of 1800 adult patients at the Haitian Study Group for Kaposi’s sarcoma and Opportunistic Infections (GHESKIO) in Haiti on antiretroviral treatment from 2003 to 2006 is published in the advance online edition of Clinical Infectious Diseases. 

Patients co-infected with tuberculosis were at increased risk for drug-induced hepatitis suggesting that targeted monitoring of co-infected patients may also be cost-effective, the authors noted.

Their results, the authors stress, show that clinical impact and cost-effectiveness vary by test and are dependent upon the antiretroviral regimen used and the prevalence of other co-morbidities such as anaemia, diabetes, hepatitis and tuberculosis. As such resource-poor settings should choose accordingly, they note.

Results compared favourably with the DART study conducted in Uganda and Zimbabwe. http://www.aidsmap.com/page/1437093/ where routine (not symptom driven) monitoring did not affect clinical outcomes.

While antiretroviral treatment improves the length and quality of life the drugs can cause life-threatening toxicities. In resource-rich settings monitoring for asymptomatic laboratory abnormalities are routine.

Within the context of limited budgets and especially in routine-poor settings where, as in the case of Haiti, laboratory costs can make up to as much as 15 percent of the total cost of HIV treatment and care, careful identification of potential cost-savings and cost-effectiveness are critical.

There is limited capacity for laboratory monitoring in resource-poor settings. Significant financial and human resources are needed to support an adequate infrastructure. Efficient use of scarce resources requires evidence-based guidelines on tests that affect care.

So these guidelines, the authors stress, should be based on studies that evaluate the clinical benefits and cost-effectiveness of individual tests.

The Haitian Study Group for Kaposi’s sarcoma and Opportunistic Infections (GHESKIO), a Haitian non-governmental organisation provides comprehensive HIV/AIDS care free-of-charge to all who present for care.

Haiti, the poorest country in the western hemisphere, has an HIV prevalence of 2.2% in the adult population with approximately 25,000 of the estimated 120,000 HIV-infected nationwide getting antiretroviral therapy. Gross domestic product per person is US$699 a year.

The standard first-line regimen since 2003 at GHESKIO is zidovudine, lamivudine and efavirenz. For women of childbearing age nevirapine is preferred to efavirenz.

The authors undertook a retrospective analysis of demographic and clinical data (antiretroviral medications and concurrent tuberculosis infection), antiretroviral monitoring test results and CD4 cell counts of 1800 patients aged 16 or over who had started antiretroviral treatment consecutively from March 1 2003 until June 6 2006.

The goal of the study was to determine the clinical benefit and cost-effectiveness of routinely monitoring for asymptomatic laboratory abnormalities among patients getting antiretroviral treatment compared to testing those with symptoms of toxicity.

Prevalence and incidence of hepatitis, renal (kidney) insufficiency, hyperglycaemia (high blood sugar), anaemia, neutropaenia, (low number of white blood cells) and thrombocytopaenia (low number of platelets) were determined according to baseline and follow-up data, respectively.

Costs for each disability-adjusted life year (DALY) averted were then calculated according to detection of laboratory abnormalities by routine (not symptom) testing compared to symptom driven testing.

The authors described a DALY as one year of ‘healthy’ life lost to early mortality or morbidity because of a disease. DALYs are calculated as the sum of the years of life lost, because of premature mortality and the years lived with disability from a disease, adjusted for the severity of that disease.

The authors estimated the risks of mortality and morbidity from published literature and calculated estimated health care costs. The cost-effectiveness ratio for each test was determined by dividing the net cost of testing by the number of DALYs averted for that test.

The World Health Organization (WHO) considers an intervention cost-effective if the ratio of cost for each DALY averted is less than three times a country’s gross domestic product (GDP) per person. For Haiti that is less than US$2097.

Laboratory costs ranged from US$0.33 for haematocrit (percentage of whole blood in red blood cells; used to test for anaemia) testing to US$6.00 for a complete blood count or liver function tests.

The median CD4 cell count at entry was 122 cells/mm³ (IQR: 74-175 cells/mm³). Median follow-up time was 910 days (IQR: 482-1185 days).

Monitoring for asymptomatic anaemia with hematocrit testing proved cost-saving at baseline with a cost-effective ratio of US$317 for each DALY averted during follow-up. At baseline 48 (3.5%) had severe anaemia and received an alternative to zidovudine. Five percent of patients (incidence rate of 2.5 cases per 100 person-years) developed zidovudine-related anaemia.

However, the authors noted that rates of anaemia would be lower if drugs not associated with anaemia were used, for example, tenofovir. So consideration of monitoring costs as well as drug costs is necessary to determine which drugs to use.

Monitoring with complete blood cell count was less cost effective (US$1182 for each DALY averted at baseline and US$10,781 for each DALY averted at follow-up) because other blood abnormalities (neutropaenia and thrombocytopaenia) made no difference in clinical outcomes

Monitoring for asymptomatic kidney and liver problems was very expensive (US$15,419 and $142,955 respectively for each DALY averted at baseline; and over US$19,036 to over US$170,455 at follow-up) and rarely affected care.

Rates of drug-induced hepatitis were similar to those in other resource-poor settings but significantly lower than in middle- and high-income countries with higher rates of injecting drug users as well as hepatitis B and C.

However, as noted above, routine testing was cost-effective in patients co-infected with tuberculosis and concurrently taking tuberculosis medication because they were at increased risk for liver abnormalities; U$477 for each DALY averted at follow-up.

The authors note their study is limited as it took place in a single country. However their results show that evidence-based policies for laboratory monitoring of patients on antiretroviral treatment are needed in resource-poor settings.

They recommend that other countries perform a similar kind of analysis before “committing a significant proportion of their antiretroviral therapy budget to laboratory tests that rarely affect clinical management and that are not cost-effective.”

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