Table 3.

Results of multivariable models predicting donation related outcomes

Outcome/Predictors (with Ordered Response Options)Estimate or OR (95% CI)P ValueModel Fit
Reasons for donating (reference group is “I volunteered to donate on my own”)aC-statistic=NA
 Response: “I was asked by someone other than my recipient”
  Time since donation, per 10 yr1.71 (1.41–2.08)<0.001
  Male (ref: female)1.62 (1.08–2.44)0.02
  Relation to recipient: parent, child, sibling, spouse, other relative (ref: not related)1.33 (0.59–3.01)0.50
Response: “I was asked by my recipient”
  Time since donation, per 10 yr1.20 (1.07–1.34)0.001
  Male (ref: female)1.49 (1.20–1.85)<0.001
  Relation to recipient: parent, child, sibling, spouse, other relative (ref: not related)2.18 (1.42–3.35)<0.001
Overall recovery time (<3 mo, 3–6 mo, >6 mo, never recovered)R2=0.01
 Race: white (ref: nonwhite)−0.13 (−0.22 to −0.04)0.005
 Surgical procedure: laparoscopic (ref: open)−0.10 (−0.15 to −0.05)<0.001
Recovery time for daily activities (<3 mo , 3–6 mo, >6 mo, never returned to usual activities)R2=0.02
 Race: white (ref: nonwhite)−0.16 (−0.21 to −0.11)<0.001
 Educational attainment at donation−0.02 (−0.03 to 0.00)0.009
Recovery time compared with expectations (much shorter than, somewhat shorter than, about as long as, somewhat longer than, much longer than I expected)R2=0.02
 Age at donation, per 10 yr0.44 (0.19–0.68)0.004
 Age at donation, per 10 yr, squared−0.06 (−0.09 to −0.03)<0.001
 Male (ref: female)−0.15 (−0.24 to −0.05)0.002
 Surgical procedure: laparoscopic (ref: open)−0.24 (−0.34 to −0.14)<0.001
Felt supported by friends and family (strongly disagree, disagree, unsure, agree, strongly agree)R2=0.02
 Time since donation, per 10 yr−0.07 (−0.11 to −0.04)<0.001
 Relation to recipient: parent, child, sibling, spouse, other relative (ref: not related)0.17 (0.07–0.27)<0.001
 Donor had at least one emotional, psychological, or substance abuse difficulty after donation−0.39 (−0.54 to −0.23)<0.001
Felt supported by health care providers (strongly disagree, disagree, unsure, agree, strongly agree)R2=0.04
 Age at donation, per 10 yr0.07 (0.03–0.11)0.001
 Male (ref: female)0.16 (0.07–0.26)0.001
 Donor had at least one medical complication after donation−0.31 (−0.43 to −0.19)<0.001
 Donor had at least one emotional, psychological, or substance abuse difficulty after donation−0.68 (−0.90 to −0.45)<0.001
Felt no one paid attention (strongly disagree, disagree, unsure, strongly agree, agree)R2=0.03
 Donor had at least one medical complication after donation0.27 (0.17–0.37)<0.001
 Donor had at least one emotional, psychological, or substance abuse difficulty after donation0.66 (0.47–0.85)<0.001
Feels closer to the recipient since donating (of donors with living recipients) (strongly disagree, disagree, unsure, strongly agree, agree)R2=0.04
 Age at donation to per 10 yr0.08 (0.03– 0.13)0.001
 Donor had at least one emotional, psychological, or substance abuse difficulty after donation−0.58 (−0.87 to −0.28)<0.001
 Donor type: Parent (ref: other unrelated)0.56 (0.33–0.79)<0.001
  Child0.61 (0.35–0.88)<0.001
  Sibling0.35 (0.13–0.57)0.002
  Spouse0.55 (0.29–0.81)<0.001
  Other0.33 (0.05–0.62)0.02
  Friend0.46 (0.20–0.73)<0.001
Thinks recipient feels indebted (strongly disagree, disagree, unsure, strongly agree, agree)R2=0.05
 Donor type: Parent (ref: other unrelated)−0.69 (−0.97 to −0.41)<0.001
  Child−0.28 (−0.60 to 0.04)0.08
  Sibling−0.22 (−0.48 to 0.05)0.11
  Spouse−0.42 (−0.74 to −0.11)0.01
  Other−0.26 (−0.60 to 0.09)0.14
  Friend−0.02 (−0.34 to 0.31)0.93
 Donor kidney is no longer functioning for the recipient (ref: is functioning)−0.32 (−0.47 to −0.16)<0.001
Thinks recipient does not show enough gratitude (strongly disagree, disagree, unsure, agree, strongly agree)R2=0.06
 Age at donation, per 10 yr−0.09 (−0.13 to −0.04)<0.001
 Donor had at least one medical complication after donation0.32 (0.20–0.44)<0.001
 Donor had at least one emotional, psychological, or substance abuse difficulty after donation0.63 (0.36–0.90)<0.001
 Donor type: Parent (ref: other unrelated)−0.24 (−0.45 to −0.03)0.02
  Child−0.33 (−0.58 to −0.09)0.007
  Sibling−0.13 (−0.33 to 0.06)0.09
  Spouse−0.03 (−0.27 to 0.21)0.79
  Other−0.17 (−0.42 to 0.09)0.20
  Friend−0.25 (−0.50 to −0.01)0.04
Overall donation experience (poor, fair, good, very good, excellent)R2=0.11
 Time since donation, per 10 yr−0.05 (−0.09 to −0.01)0.008
 Donor had at least one medical complication after donation−0.49 (−0.57 to −0.40)<0.001
 Donor had at least one emotional, psychological, or substance abuse difficulty after donation−0.93 (−1.09 to −0.76)<0.001
 Donor kidney is no longer functioning for the recipient (ref: is functioning)−0.11 (−0.18 to −0.04)0.003
If possible, would donate again (definitely not, probably not, not sure, probably yes, definitely yes)R2=0.04
 Time since donation, per 10 yr−0.04 (−0.06 to −0.01)0.003
 Race: white (ref: non−white)0.14 (0.05–0.22)0.002
 Relation to recipient: parent, child, sibling, spouse, other relative (ref: not related)0.10 (0.03–0.17)0.005
 Donor had at least one medical complication after donation−0.09 (−0.15 to −0.03)0.002
 Donor had at least one emotional, psychological, or substance abuse difficulty after donation−0.44 (−0.55 to −0.33)<0.001
Difficulty paying monthly household billsa (no, yes)C−statistic=0.75
 Age at donation, per 10 yr0.62 (0.51–0.75)<0.001
 Time since donation, per 10 yr0.75 (0.60–0.93)0.009
 Educational attainment at donation0.58 (0.46–0.73)<0.001
 Donor had at least one medical complication after donation2.21 (1.46–3.34)<0.001
 Donor had at least one emotional, psychological, or substance abuse difficulty after donation4.30 (2.48–7.46)<0.001
Donation caused a financial burden (no burden, little burden, moderate burden, great burden, extreme burden)R2=0.07
 Age at donation, per 10 yr−0.05 (−0.07 to −0.02)<0.001
 Educational attainment at donation−0.06 (−0.08 to −0.03)<0.001
 Donor had at least one medical complication after donation0.18 (0.11–0.25)<0.001
 Donor had at least one emotional, psychological, or substance abuse difficulty after donation0.65 (0.52–0.78)<0.001
Poor psychosocial outcome (defined as having at least one of the following: fair/poor overall donation experience; great/extreme financial burden due to donation; probably/definitely not donate again; emotional, psychological or substance abuse use difficulty due to donation; or discomfort with decision to donate)aC−statistic=0.57
 Donor kidney is no longer functioning for the recipient (ref: functioning)1.77 (1.33–2.34)<0.001
  • OR, odds ratio; 95% CI, 95% confidence interval; ref, reference; NA, not available.

  • a Modeled using binary logistic or multinomial logistic regression; statistics reported are ORs and 95% CIs. Models not marked with the "a" footnote used linear regression, and statistics reported are β coefficients and 95% CIs. When assessing the fit of a binary (but not available for multinomial) logistic regression, a c-statistic of 0.5 indicates prediction no better than chance, whereas a c-statistic of 1.0 indicates perfect prediction of the outcome. Multinomial logistic regressions do not provide a c-statistic. In linear regression, R2 is the proportion of variance of the outcome that is explained by the predictor variables; R2 ranges between 0 (no prediction) and 1 (perfect prediction). Estimates from linear regressions can be interpreted as the difference in the outcome per one-unit higher value in the predictor. For instance, the −0.13 estimate for race in the model predicting overall recovery time indicates that white donors recovered 1/8 point faster on a 4-point scale relative to nonwhite donors. Without adjustment for surgical procedure, 74% of white donors recovered within 3 months, compared with 67% of nonwhite donors. ORs can be interpreted as the difference in the odds of the outcome, per one unit higher value in the predictor. For example, the odds of donors with at least one medical complication having difficulty paying household bills are 121% higher (OR, 2.21) than the odds of donors without a medical complication having difficulty paying household bills.