Table 4 Summary of reported multiple regression analyses in included studies
Study | Type of regression model | Results of analysis | Notes | ||
|---|---|---|---|---|---|
Dependent variable | β-coefficient | p-value |  | ||
(SE) | |||||
predictors of tto values | Â | Â | Â | Â | Â |
Brown et al. [30] | OLS regression | VA (Snellen) in BSE | 0.37 | <0.0001 | The following equation was developed from the model: |
| Â | Â | Â | Â | Â | Utility value = 0.37 (VA) + 0.514, |
Brown et al. [31] | OLS regression | VA (Snellen), 1 'good’ eye | -0.0902 | 0.001 | Significant differences in reported utility values were noted when patients with two 'good’ eyes (bilateral good vision) were compared with those with one 'good’ eye (unilateral good vision). |
Brown et al. [32] | OLS stepwise model | VA (Snellen), BSE | NR | <0.0001 | A significant relationship was demonstrated between decreasing vision in the BSE and decrements in utility values. This relationship was absent for VA in the WSE. |
| Â | Â | VA (Snellen), WSE | NR | 0.43 | Â |
Espallargues et al. [22] | OLS Stepwise model | Distant VA (logMAR), BSE | -0.04 | 0.686 | An association was observed between distant VA in the BSE and TTO scores. Selection criteria for significant predictors were p < 0.1. Age and time since diagnosis were important for TTO values. |
(0.05) | |||||
Sharma et al. [34] | OLS model | VA (logMAR), BSE | 0.176 | <0. 01 | VA levels in both the affected eye (p < 0.01) and unaffected eye (p < 0.01) were independently associated with reported utilities. Better vision was associated with higher scores. |
predictors of sg values | Â | Â | Â | Â | Â |
Lloyd et al. [24] | Mixed model analysis | VA (Snellen), BSE | NR | NR | The VA levels were based on the levels of vision used in the health state cards developed for the study. The authors reported that described states were significant in predicting utility. Further analysis showed that SG values were not associated with a patient’s visual acuity level. |
Sharma et al. [34] | Bivariate analysis | VA (logMAR), BSE | 0.193 | <0. 01 | VA levels in both the affected eye (p < 0.01) and unaffected eye (p < 0.01) were independently associated with reported utilities. Better vision was associated with higher scores. |
| Â | Multivariate analyses | Â | Â | Â | Â |
predictors of hui-3 values (global) | Â | Â | Â | Â | Â |
Espallargues et al. [22] | Multiple linear regression | Distant VA (logMAR), BSE | -0.12 | 0.226 | A selection criterion of p < 0.1 was adopted for a backward stepwise regression model of relevant variables. Significant variables were contrast sensitivity, illness (es) of long duration and age. |
(0.43) | |||||
| Â | Univariate regression | VA (logMAR), BSE | -0.14 | <0.01 | Â |
(0.03) | |||||
Sahel et al. [26] | Multiple regression | BSE: WSE | NR | NR | The adjusted R-squared showed that 21% of the variance in the global score was due to the VA levels [p < 0.01 (BSE); p = 0.31(WSE)]. |
|  |  | ≥20/40: ≥ 20/200 | 0.6 | NR |  |
|  |  | ≥20/40: < 20/200 | 0.57 | NR |  |
|  |  | <20/40: ≥ 20/200 | 0.41 | NR |  |
| Â | Â | < 20/40: <20/200 | 0.42 | NR | Â |
predictors of hui-3 values (vision dimension) | Â | Â | Â | Â | Â |
Espallargues et al. [22] | Univariate regression | VA (logMAR), BSE | -0.25 | <0.01 | Â |
(0.26) | |||||
| Â | Multivariate analyses | VA (logMAR), BSE | -0.21 | <0.01 | Â |
(0.04) | |||||
Sahel et al. [26] | Multiple regression | BSE: WSE | Â | Â | Authors reported that 36% of the variance in the visual dimension of the HUI-3 score was expressed by the adjusted R-squared value [p < 0.01 (BSE); p = 0.7(WSE)]. |
|  |  | ≥20/40: ≥ 20/200 | 0.75 | NR |  |
|  |  | ≥20/40: < 20/200 | 0.74 | NR |  |
|  |  | <20/40: ≥ 20/200 | 0.42 | NR |  |
| Â | Â | < 20/40: <20/200 | 0.37 | NR | Â |