Plain English summary
Introduction
Methods
Study design
Study participants
Study instruments
NI Diary
Night-time voiding diary
Patient Global Impression (PGI): Severity and Improvement
Exit interviews
Analytical methods
Quality of completion
Item distribution and floor and ceiling effects
Inter-item correlations and item-total correlations
Item discrimination indices and curves
Confirmatory factor analysis
Internal consistency
Test–retest reliability
Convergent validity
Known-groups validity
Interpretation of scores: meaningful change threshold (MCT)
Anchor-based methods
Cumulative distribution function (CDF) curves
Receiver operating characteristic (ROC) curves
Distribution-based methods
Results
Participant baseline demographics
Demographic category | Study population N = 302 | Exit interview population N = 66 |
---|---|---|
Sex, n (%) | ||
Female | 180 (59.6) | 37 (56.1) |
Male | 122 (40.4) | 29 (43.9) |
Age (years) | ||
Mean (SD) | 58.8 (12.82) | 57.3 (13.17) |
Median | 60.5 | 57 |
Min, Max | 50, 68 | 21, 84 |
Race, n (%) | ||
American Indian or Alaska Native | 3 (1.0) | 2 (3.0) |
Asian | 5 (1.7) | 1 (1.5) |
Black or African American | 28 (9.3) | 8 (12.1) |
White | 264 (87.4) | 54 (81.8) |
Unknown | 2 (0.7) | 1 (1.5) |
Ethnicity, n (%) | ||
Hispanic or Latino | 105 (34.8) | |
Not Hispanic or Latino | 195 (64.6) | |
Unknown | 2 (0.7) |
Quality of completion
Floor and ceiling effects
Baseline | Week 1 | Week 12 | ||||
---|---|---|---|---|---|---|
Ceiling (%) | Floor (%) | Ceiling (%) | Floor (%) | Ceiling (%) | Floor (%) | |
Benchmark (%) | 20 | 20 | 20 | 20 | 20 | 20 |
Item 1: Difficult to concentrate | 13.5 | 4.1 | 24.8 | 2.4 | 47.2 | 0.4 |
Item 2: Low in energy and/or tired | 6.4 | 10.5 | 15.7 | 4.2 | 29.2 | 0.4 |
Item 3: Unable to be productive or complete daily activities | 14.5 | 5.7 | 30.4 | 2.8 | 49.8 | 0.7 |
Item 4: Avoid participating in activities | 17.6 | 5.4 | 34.3 | 2.8 | 55.0 | 0.7 |
Item 5: Irritable or moody | 17.9 | 6.4 | 32.2 | 2.1 | 49.4 | 1.8 |
Item 6: Limit your fluid intake | 23.6 | 5.4 | 28.7 | 2.8 | 42.1 | 1.1 |
Item 7: Lay awake after using the bathroom at night | 6.4 | 9.8 | 16.8 | 3.8 | 36.2 | 1.5 |
Item 8: Worried about tripping or falling | 37.8 | 3.7 | 48.6 | 2.4 | 64.9 | 1.8 |
Item 9: Got too little sleep | 3.7 | 16.2 | 14.0 | 5.9 | 34.7 | 2.2 |
Item 10: Worry that the nocturia will get worse | 2.4 | 20.9 | 6.3 | 10.5 | 15.5 | 7.7 |
Item 11: Concerned with where the bathroom is | 14.9 | 17.9 | 24.1 | 12.6 | 34.7 | 9.2 |
Item 12: Does nocturia presently impact your life? | 2.4 | 21.6 | 7.3 | 11.5 | 19.2 | 6.6 |
Item-total correlations and inter-item correlations
Item discrimination indices and curves
Confirmatory factor analysis
Baseline | χ2 | df | P-value | CFI | TLI | RMSEA (90% CI) | SRMR | Range of standardized factor loadings |
---|---|---|---|---|---|---|---|---|
Unadjusted 11-item model | 281.648 | 44 | < .001 | 0.952 | 0.940 | 0.141 (0.125–0.157) | 0.043 | .64–.85 |
Adjusted 11-item model (with 2 residual correlations) | 134.165 | 42 | < .001 | 0.981 | 0.976 | 0.090 (0.073–0.107) | 0.031 | .64–.85 |
Internal consistency
Test–retest reliability
Convergent validity
Known-groups validity
Interpretation of scores: MCT
Exit interviews
Correlation between the endpoint and anchors
Anchor-based Analysis
Anchor | Change | N | Mean (SD) | Median | 95% CI of Mean | P-valueb | SES of Changec |
---|---|---|---|---|---|---|---|
Nocturnal Voids | > − 0.5 to < 0.5 | 21 | − 8.0 (14.62) | − 1.5 | (− 14.65, − 1.34) | 0.021 | − 0.55 |
> − 1.5 to − 0.5 | 73 | − 14.7 (21.22) | − 10.6 | − 19.68, − 9.78 | < .0001 | − 0.69 | |
> − 2.5 to − 1.5 | 83 | − 22.0 (24.22) | − 17.4 | (− 27.31, − 16.74) | < .0001 | − 0.91 | |
PGI-S | No Change (0) | 59 | − 6.0 (13.91) | − 3.4 | (− 9.65, − 2.40) | 0.0015 | − 0.43 |
1-Point Improvement (− 1) | 100 | − 17.4 (18.61) | − 14.8 | (− 21.13, − 13.74) | < .0001 | − 0.94 | |
PGI-I | No Change | 33 | − 1.5 (10.39) | − 0.8 | (− 5.15, 2.22) | 0.4227 | − 0.14 |
A Little Better | 46 | − 8.0 (15.34) | − 5.9 | − 12.55, − 3.44 | 0.0010 | − 0.52 | |
Much Better | 74 | − 20.4 (20.92) | − 16.7 | (− 25.23, − 15.54) | < .0001 | − 0.97 | |
PGI-Interview | No Change | 13 | 0.8 (10.85) | 0 | (− 5.80, 7.31) | 0.8054 | 0.07 |
A Little Better | 10 | − 8.2 (14.02) | − 5.9 | − 18.21, 1.85 | 0.0981 | − 0.58 | |
Much Better | 17 | − 21.9 (16.61) | − 21.2 | (− 30.40, − 13.32) | < .0001 | − 1.32 | |
NI Diary Q12 | No Change (0) | 98 | − 7.3 (11.32) | − 5.3 | (− 9.55, − 5.01) | < .0001 | − 0.64 |
1-Category Improvement (− 1) | 67 | − 18.7 (13.81) | − 18.9 | (− 22.06, − 15.33) | < .0001 | − 1.35 |