An observational cohort study to evaluate the impact of the tenofovir-based single tablet regimens on adherence, quality of life and cost-effectiveness in HIV-1 infected patients (GUESS)

Study type

• Study topic:
  Disease /health condition

  Human medicinal product
• Study type:
  Non-interventional study
• Scope of the study:
  Effectiveness study (incl. comparative)

  Other
• If ‘other’, further details on the scope of the study:
  Adherence
• Data collection methods:
  Primary data collection

Non-interventional study

• Non-interventional study design:
  Cohort

Study drug and medical condition

• Medical condition to be studied:
  HIV infection WHO clinical stage I

Population studied

• Short description of the study population:
  Adult HIV-1 infected subjects who initiated cART between 1st January 2008 and 30th June 2015 according to EACS Guidelines in force at the time.; Subjects must meet all of the following inclusion criteria:; 1. Subjects who give written informed consent.; 2. HIV-1 infected subjects, aged 18 years or older at time of introduction of first cART.; 3. Availability of complete antiretroviral therapy clinical history and pharmacy refills (pharmacy’s electronic database).; 4. Subjects who initiated therapy with a regimen containing one boosted protease inhibitor (PI/r) plus two Nucleoside Reverse Transcriptase Inhibitors (2NRTI) or one Non-nucleoside Reverse Transcriptase Inhibitor (NNRTI) plus 2NRTI or one integrase inhibitor (INSTI) boosted or not plus 2NRTI, according to the EACS Guidelines in force at the time
• Age groups:
  • Adults (18 to < 46 years)
  • Adults (46 to < 65 years)
  • Adults (65 to < 75 years)
  • Adults (75 to < 85 years)
  • Adults (85 years and over)
• Special population of interest:
  Immunocompromised
• Estimated number of subjects:
  860

Study design details

• Main study objective:
  To prospectively evaluate the impact of tenofovir-based single tablet regimens (STR) on adherence in HIV-1 infected subjects. Adherence was assessed using the CEAT-VIH, which is an instrument for the assessment of adherence rates to cART in HIV-infected subjects.
• Outcomes:
  Adherence:Mean score of CEAT-VIH questionnaire in the subgroup of subjects of the STR cohort who were on tenofovir-based at the time the questionnaire was administered, compared to the mean score of the same questionnaire among subjects in the control cohort. Comparison was performed at enrolment, 12 months and at 24 months, after adjusting for baseline variables and other confounders. Quality of lifeAdherenceEffectiveness, safety and tolerabilityCosts & hospitalization
• Data analysis plan:
  For qualitative data, absolute and relative frequencies were presented. Percentages were based on the total number of subjects with non-missing values unless specified otherwise. Counts for missing values were also tabulated but missing values were not considered in the percentages.For quantitative data, mean, standard deviation, median, 25th and 75th percentiles, minimum, and maximum and number of non-missing cases (95% confidence intervals for parameters of interest) were presented.Comparisons intra-patient for two paired quantitative variables were carried out using linear models or Wilcoxon Sign-Rank test if normality assumption was not accepted.In order to maximize homogeneity between the two cohorts and reduce the impact of treatment-selection bias a propensity score matching (PSM) approach was applied in the statistical analysis.Matched comparisons used conditional logistic regression when the outcome was binary or ordinal.