Interobserver variability for retreatment indications after Ranibizumab loading doses in neovascular age-related macular degeneration.
OBJECTIVE
To assess the interobserver variability (IOV) in indicating retreatment for neovascular Age-related macular degeneration 4 weeks after three Ranibizumab loading doses using spectral domain OCT (SD-OCT) as the primary objective diagnostic tool.


METHODS
Four observers decided for or against 4th Ranibizumab injection in 108 patients by six different rating rounds (RR) based on the SD-OCT findings after the loading doses. Postoperative OCT images were supplemented consecutively with information from a chart review as the 'patients subjective estimation of vision (SE)', the course of best-corrected visual acuity (BCVA) and the preoperative OCT as well as all information collectively. Agreement rates (AR) and Kappa statistics were calculated.


RESULTS
Based on post-treatment OCT findings only (RR1), mean reinjection rate of all observers was 37.5%. Adding supplementary information, mean reinjection rate decreased to 20% when all information was available reflecting the 'real' situation (RR 6). Interobserver agreement rates varied from 66.7% to 90.7% depending on rating rounds and interobserver pairs. Mean AR and Kappa values (KV) were as following: AR 81.6%, KV 0.61 (RR1: 'only post-OP OCT'); AR 76.7%, KV 0.33 (RR2: post-OP OCT + SE); AR 80.3%, KV 0.45 (RR3: post-OP OCT + BCVA); AR 80.7%, KV 0.46 (RR4: pre- and post-OP OCT); AR 82.2%, KV 0.49 (RR5: post-OP OCT + SE + BCVA); and finally AR 83.6%, KV 0.47 (RR6: pre- and post-OP OCT + SE + BCVA). The overall mean agreement rate was 80.9% with a Kappa of 0.47.


CONCLUSIONS
IOV for indicating retreatment after three Ranibizumab loading doses reveals only moderate agreement in Kappa statistics, which seems to be too low considering the high costs for retreatments. More concise guidelines based on the post-treatment OCT scans as the presumably most sensitive and noninvasive objective tool to follow choroidal neovascularization activity by judging the course of sub- and intraretinal fluid are necessary.
Framme
Carsten
C
University Eye Hospital Regensburg, Germany University Eye Hospital Bern, Switzerland. carsten.framme@insel.ch
Panagakis
Georgios
G
Walter
Andreas
A
Gamulescu
Maria Andreea
MA
Herrmann
Wolfgang
W
Helbig
Horst
H
D020533:Angiogenesis Inhibitors / Q000008:administration & dosage*; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage*; D006801:Humans; D058449:Intravitreal Injections; D015588:Observer Variation; D000069579:Ranibizumab; D015203:Reproducibility of Results; D012160:Retina / Q000473:pathology*; D019233:Retreatment; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology; D057135:Wet Macular Degeneration / Q000175:diagnosis* / Q000188:drug therapy* / Q000503:physiopathology
D020533:Angiogenesis Inhibitors; D061067:Antibodies, Monoclonal, Humanized; D000069579:Ranibizumab