Verteporfin photodynamic therapy for neovascular age-related ...

DOI: 10.3310/hta16060Health Technology Assessment 2012; Vol. 16: No. 647B: Is ‘outcome’ the same in the NHS as in randomised trials?This analysis included 4043 eyes of the 4043 patients who had a diagnosis of nAMD and a firsttreatment > 350 days before the close of the study. As described in Chapter 4, Definition of ‘TAP’eligibility, eyes were classified as EFT, IFT or UNC. BCVA outcome in the EFT subgroup was ofprimary interest in addressing objective B. In order to maximise the power of the analysis, allthree subgroups were included in one mixed regression analysis that included the TAP eligibilitysubgroup and baseline lesion classification (predominantly classic, minimally classic, occultonly; Table 12). The possibility of a differing gradient of change over time by subgroup was testedby fitting an interaction of TAP eligibility subgroup and time, but this was found to be nonsignificantand was excluded from the final model.We compared descriptively the change in BCVA in the two angiographic subtypes in ourstudy with those previously reported for treatment and sham treatment arms in the TAP trials(Figure 7). 4,30 Both the fitted trajectory and the absolute changes in BCVA over time for patientswith predominantly classic lesions in the EFT group were similar to those for patients in the TAPtreatment arm. For eyes with minimally classic lesions in the EFT group, the trajectory of BCVAwas parallel to that observed for the minimally classic subgroup of the TAP treatment arm butshowed less absolute loss of BCVA (Figure 8). 4,30Baseline lesion classification influenced outcome. Within the EFT group, eyes with minimallyclassic CNV had better BCVA at baseline (+1.13 letters; see Table 12) and deteriorated moreslowly than eyes with predominantly classic CNV (+1.13 + 2.08 = +3.2 letters at 1 year; seeTable 12).The influences of several covariates on BCVA were also investigated, partly because the covariatescould have confounded the influences of the TAP eligibility subgroup and baseline lesionclassification, and partly because their possible influences were of interest in their own right. Thecoefficients from the final mixed regression model, shown in Table 12, show that a number ofbaseline covariates did indeed influence BCVA. None of these statistically significant covariatesinteracted with the TAP eligibility subgroup, so they can be considered to apply equally to theEFT, IFT and UNC subgroups.The rate of deterioration of BCVA was influenced by baseline acuity, with faster decline in BCVAover time in eyes with better starting acuity; a patient who read five letters more than averageat baseline read only 2.7 letters more at 1 year. BCVA deteriorated faster in older patients; after1 year of follow-up, BCVA was two letters worse for a person 10 years older than average (88 vs78 years). Women presented with better baseline BCVA and maintained this difference duringfollow-up (+1.8 letters). Ex-smokers and those who had never smoked presented with betterbaseline BCVA (+1.6 and +1.8 letters respectively) and deteriorated more slowly than currentsmokers. The decrease in BCVA by 1 year was one letter fewer in treated eyes of ex-smokers, andthree letters fewer in treated eyes of never smokers, than in treated eyes of current smokers. If thefellow eye had better BCVA than the treated eye, BCVA in the treated eye was worse at baseline(+2.6 letters) and deteriorated faster; the decrease in BCVA by 1 year was five letters worse than ifthe treated eye was classified as the better-seeing eye. The decrease in BCVA over 1 year was 8 to16 letters depending on patients’ characteristics and lesion factors (see C: Is ‘outcome’ the same forpatients excluded from randomised trials? below).© Queen’s Printer and Controller of HMSO 2012. This work was produced by Reeves et al. under the terms of a commissioning contract issued by theSecretary of State for Health.