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Table 5 Predictors for being in the best tertile of TSQM total and domain scores

From: Subcutaneous immunoglobulin in primary immunodeficiency – impact of training and infusion characteristics on patient-reported outcomes

Predictor Category Logistic regression Linear regression
OR 95% CI p-value Coefficient 95% CI p-value
Total
 Age 0–17 years 1   0.08 0   0.005
≥18 years 0.51 0.23, 1.09 −7.3 −12.3, −2.2
 Time on treatment ≤2 years 1   0.008 0   0.03
> 2 years 2.07 1.21, 3.52 4.0 0.5, 7.5
 Ease of traininga 1–5     0   0.05
6–7 4.2 0.0, 8.4
 Confidence after traininga 1–5 1   0.03 0   0.001
6–7 1.89 1.08, 3.33 6.6 2.7, 10.4
 Barriers to training Yes 1   0.06 0   0.002
No 1.96 0.96, 4.00 6.6 2.4, 10.8
 Infusion preparation duration > 20 mins 1   0.08 n/s n/s n/s
≤20 mins 1.59 0.95, 2.65
Effectiveness
 Time on treatment ≤2 years 1   0.004 0   0.05
> 2 years 2.56 1.35, 4.88 5.7 −0.1, 11.4
 Training sessions required 1–3     0   0.01
≥4 −7.5 −13.1, −1.8
 Barriers to training Yes 1   0.01 0   0.005
No 2.43 1.23, 4.81 8.5 2.6, 14.4
Side effects
 Age 0–17 years 1   0.04 0   0.007
≥18 years 0.45 0.21, 0.96 −10.7 −18.4, −2.9
 Time on treatment ≤2 years 1   0.003 0   0.03
> 2 years 2.36 1.34, 4.16 7.1 0.7, 13.4
 Training sessions required 1–3     0   0.05
≥4 −6.8 −13.5, −0.1
 Confidence after traininga 1–5 1   0.004 0   < 0.001
6–7 2.04 1.25, 3.32 11.1 5.7, 16.4
 Infusion preparation duration > 20 mins 1   0.007 0   0.002
≤20 mins 1.88 1.19, 2.98 8.1 3.1, 13.1
 Actual infusion time > 2 h 1   0.03 n/s n/s n/s
≤2 h 1.70 1.06, 2.73
 Frequency of infusions > 1 per week 1   0.008 0   0.003
Weekly/up to every 2 weeks 4.09 1.66, 10.10 14.5 5.3, 23.7
Every 3 or 4 weeks 4.68 1.54, 14.20 19.5 8.1, 30.9
Convenience
 Age 0–17 years 1   0.03 0   0.01
≥18 years 0.41 0.19, 0.92 −7.4 −13.1, −1.7
 Experience on SCIG ≤2 years 1   0.04    
> 2 years 1.80 1.02, 3.12
 Ease of traininga 1–5     0   0.003
6–7 7 2.5, 11.6
 Confidence after traininga 1–5 1   0.001 0   < 0.001
6–7 3.00 1.59, 5.65 7.9 3.6, 12.2
 Barriers to training Yes 1   0.04 0   0.006
No 2.23 1.02, 4.88 6.6 1.9, 11.4
 Infusion preparation duration > 20 mins 1   < 0.001 0   0.05
≤20 mins 1.95 1.13, 3.35 3.8 0.0, 7.5
Global
 Age 0–17 years 1   0.04 0   0.007
≥18 years 0.46 0.22, 0.96 −8.0 −13.8, −2.2
 Time on treatment ≤2 years 1   0.001 0   < 0.001
> 2 years 3.39 1.66, 6.93 10.7 6.1, 15.3
 Competence of trainera 1–5 1   0.001    
6–7 3.47 1.66, 7.22
 Confidence after traininga 1–5     0   0.002
6–7 6.4 2.5, 10.4
 Length of training session ≤2 h 1   0.006 0   0.01
> 2 h 2.02 1.22, 3.35 4.8 1.0, 8.7
 Infusion preparation duration > 20 mins 1   0.03 0   0.001
≤20 mins 1.76 1.07, 2.97 6.2 2.5, 9.8
  1. Treatment satisfaction – multivariate logistic regression and linear regression models calculated predictors for being in the best tertile of TSQM total and domain scores. TSQM scores were transformed to a 1–100 scale (1 = worst satisfaction and 100 = perfect satisfaction), where respondents were grouped in T2 + T3 (intermediate/worst) if they had a lower score and in T1 (best) if they had a higher score (see Table 2 for exact tertile ranges)
  2. CI confidence interval, n/s not significant, OR odds ratio, SCIG subcutaneous immunoglobulin, TSQM Treatment Satisfaction Questionnaire for Medication
  3. aPredictor on an anchored numeric scale from 1 to 7 (1 = very difficult or not very confident/competent and 7 = very easy or very confident/competent). The logistic regression provides an OR which predicts the likelihood of that category falling into T1, where the higher number corresponds to better odds. The least squares regression considers scores on a continuous scale using the 0–100 scale, where a higher coefficient implies a higher TSQM score
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BMC Immunology

ISSN: 1471-2172

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