Background The aims of highly active antiretroviral therapy (HAART) in HIV-infected children are to achieve and sustain full HIV-RNA viral load (VL) suppression and CD4-reconstitution, in order to prevent the progression of the HIV infection and allow normal growth and development.

Adherence to HAART is a strong predictor of therapeutic efficacy. Previous studies have shown that therapeutic success requires adherence > 95%. Among paediatric HIV patients, adherence to HAART is reportedly suboptimal.

There are a number of factors that can compromise treatment compliance. These can be classified as those related to the medicine, the patient, the family/caregiver and the healthcare system.

Purpose To estimate the correlation between adherence to HAART and treatment efficacy.

To assess factors related to non-adherence among HIV-infected children.

Materials and Methods Retrospective cohort study from January 2008 to July 2012 including all HIV-infected patients on HAART followed by the Paediatrics Department.

Age, sex, lipoatrophy, number of pills/day (P/d) and frequency of daily dosing: once a day (QD) or twice a day (BID), were analysed.

Adherence was assessed by using the pharmacy refill records and pill count, according to the following formula:

Adherence (%) = (Nº dispensed doses- Nº returned doses)/Nº prescribed doses × 100

Undetectable VL was defined as VL < 20 copies/ml.

Data were analysed by multiple logistic regression methods using SPSS software (version 19.0).

Results 24 HIV-infected patients were included (mean age = 15.3 ± 5.5 years; 29.2% male, 70.8% female).

37.5% of patients presented lipoatrophy.

54.2% and 45.8% of the children were treated with a QD and BID regimen, respectively.

Only 50% of patients were considered adherent to treatment (adherence >95%).

The relationship between risk factors and adherence was: see Table

Patients with poor adherence had a higher risk of virological failure (OR = 11.67; CI95 = 1.14–119.54;p = 0.039)

Conclusions Adherence to HAART represents a significant challenge in the paediatric HIV population.

The P/d was significantly associated with adherence. Every pill/day increased up to 2.3-fold the risk of non-adherence to HAART.

Simplifying HAART by reducing the pill burden may contribute to improving compliance in the paediatric HIV population.

No conflict of interest.