June 2015
Volume 56, Issue 7
Free
ARVO Annual Meeting Abstract  |   June 2015
Quantifying functional reading independence in geographic atrophy: the FRI Index
Author Affiliations & Notes
  • Elizabeth Tschosik
    Genentech, Inc, South San Francisco, CA
  • Nancy Kline Leidy
    Evidera, Bethesda, MD
  • Miriam Kimel
    Evidera, Bethesda, MD
  • Chantal Dolan
    CMD Consulting, Inc, Sandy, UT
  • Eric Souied
    Centre Hospitalier Intercommunal, Creteil, France
  • Rohit Varma
    USC Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA
  • Neil M Bressler
    Retina Division, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD
  • Footnotes
    Commercial Relationships Elizabeth Tschosik, Genentech (E); Nancy Kline Leidy, Genentech (C); Miriam Kimel, Genentech (C); Chantal Dolan, Genentech, Inc (C), Iconic Therapeutics (C), Medivation, Inc (C); Eric Souied, Allergan (C), Allergan (F), Bayer (C), Novartis (C), Novartis (F), Thea (C); Rohit Varma, AAerie Pharmaceutical (F), Allergan, Inc (F), Genenteh, Inc (F), ISARNA (F), Merck & Co, Inc (F), National Eye Institute (F), Replenish, Inc (F); Neil Bressler, Bayer (F), Emmes (F), Genentech, Inc (F), Northwestern University (F), Novartis Pharma AG (F), Regeneron (F)
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science June 2015, Vol.56, 4789. doi:
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      Elizabeth Tschosik, Nancy Kline Leidy, Miriam Kimel, Chantal Dolan, Eric Souied, Rohit Varma, Neil M Bressler; Quantifying functional reading independence in geographic atrophy: the FRI Index. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):4789.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract
 
Purpose
 

Visual acuity (VA) does not fully capture impact of geographic atrophy (GA) on vision function. Thus, this study evaluated measurement properties of the Functional Reading Independence (FRI) Index and quantified difficulties with functional reading reported by GA patients, in anticipation of using the FRI Index in clinical trials of GA treatments.

 
Methods
 

Data were analyzed from MAHALO, a multi-center, randomized, single-masked, sham-controlled, phase 2 trial that evaluated lampalizumab for GA secondary to age-related macular degeneration (AMD). Subjects received injections of sham or lampalizumab in one eye monthly or every other month for 18 mo. The FRI Index, a measure of self-reported independence performing everyday reading activities, was interviewer-administered every 6 mo. Treatment arms were collapsed for psychometric analyses (n=100), which included the application of item response theory (IRT) and tests of reliability, validity and responsiveness to change in lesion size.

 
Results
 

The 7-item FRI Index scores range from 1 (unable to do) to 4 (totally independent); mean score (SD) was 2.5 (0.8) at baseline (n=94) and worsened to 2.2 (0.9) at month 18 (n=81). The proportion of subjects at Level 1 (unable to do) increased from 17% at baseline to 30% at month 18 (difference: 13%). FRI Index internal consistency (IRT marginal reliability) was 0.90. Test-retest reliability (intraclass correlation coefficient) in subjects who remained stable on the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25) from baseline to month 6 was 0.86 (n=27). FRI Index scores were correlated with NEI VFQ-25 (r=0.66; P<0.001) and GA lesion size (r=−0.26, P=0.02). No relationship was found with high contrast best-corrected VA (r=0.16; P=0.11). The FRI Index showed a trend in mean (SD) known-groups validity based on GA lesion size of <4 disc areas (<10mm2) vs ≥4 disc areas (≥10mm) (2.9 [0.8] vs 2.4 [0.8]; P=0.06). Scores were sensitive to within-subject change in GA lesion size over time, with those having an increase in lesion size over 18 mo (≥0.94mm2) showing greater FRI deterioration than those whose lesion was stable (<0.94mm2) (−0.3 vs −0.1, P=0.02).

 
Conclusions
 

Patients with GA in MAHALO experienced impairment in functional reading independence that worsened by 18 mo. This study supports the use of the FRI Index as a tool to assess functional reading independence in patients with GA secondary to AMD.

 
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