310 patients were included into this study. Demographic and baseline clinical characteristics are shown in Table 1. Response rates were above 90% for all scales and time points.
Except for 6 men, all patients did not use any pads at baseline. During the follow-up period, younger patients used less pads than older patients, but differences diminished at 12 months. At 3 months, the 0-pad-continence rate was 41.7% in the youngest age group as compared to 23.3% in the oldest age group. In all 3 age groups, 24.4% used a safety pad without having an involuntary loss of urine. 12 months after RP, 69.1% of the youngest patients did not use any pads compared to 60.0% in the oldest age group. The rate of patients using a safety pad ranged from 15.4% in the youngest age group to 18.9% in the oldest age group. The numbers of patients who experienced a decrease from baseline are shown in Table 2a. At 3 and 6 months, the proportion of the oldest patients who experienced a decrease was significantly higher than in the youngest age group. This finding was also reflected by the odds of worsening that were twice as high for the oldest as compared to the youngest age group at 3 and 6 months (see Table 2a). However, at 12 months, the rates of worsening did not differ significantly. In the logistic regression model, the odds of worsening were more than three times smaller for patients who underwent bilateral nerve-sparing as compared to patients with unilateral nerve-sparing (OR 0.29, 95% CI [0.13, 0.61], p < 0.001).
Urinary symptom scores were better in younger patients from baseline to 12 months. There were moderate cross-sectional age differences at baseline, but these diminished during the follow-up. At 12 months, cross-sectional age differences were negligible. As can be seen in Table 3a, younger patients had larger decreases at 3 and 6 months. At 12 months, the oldest patients had better scores than at baseline, while younger patients had persistent decreases. This finding was underlined by the rates of worsening (see Table 2b). At 6 and 12 months, a significantly higher proportion of the youngest patients had relevant decreases as compared to the older patients. The logistic regression model confirmed that older patients had a lower risk of worsening as compared to the youngest patients (age 61–65: OR 0.56, 95% CI [0.30, 1.04], p = 0.061, age > 65: OR 0.31, 95% CI [0.16, 0.60], p < 0.001). The odds of worsening of patients with bilateral nerve-sparing were less than half compared to patients with unilateral nerve-sparing (OR 0.46, 95% CI [0.23, 0.92], p = 0.025).
IIEF-5 scores were better in younger patients from baseline to 12 months (see Table 3b). These cross-sectional age differences were of moderate size considering the effect measure Cohen’s d. However, rates of worsening did not differ significantly between age groups (see Table 2c) and decreases were generally very large. Even at 12 months, scores remained far below baseline levels. The logistic regression model showed that bilateral nerve-sparing was associated with less than half the odds of worsening as compared to unilateral nerve-sparing (OR 0.41, 95% CI [0.21, 0.81], p = 0.01). Older patients had a lower risk of worsening than the youngest patients. However, because of the interaction effect LRP x age group, this effect was only strong for RARP patients (see Supplementary Table 1).
Global health perception/general QOL
Cross-sectional age differences were trivial at baseline and at 3 months. However, at 6 and 12 months, the oldest patients had slightly better scores than the youngest patients (see Table 3c). When considering the anchor-based criteria for longitudinal change by Cocks 2012 , almost half of the study population experienced a relevant decreases at 3 months. At 12 months, a significantly higher percentage of the youngest patients had persistent decreases as compared to the oldest patients (see Table 2d). The odds of worsening, as seen in the logistic regression model, were half the size for patients aged 61–65 (OR 0.52, 95% CI [0.27, 0.98], p = 0.039) and patients aged > 65 (OR 0.50, 95% CI [0.26, 0.94], p = 0.028) when compared to patients aged ≤ 60. Bilateral nerve-sparing was associated with less than half the odds of worsening as compared to unilateral nerve-sparing (OR 0.38, 95% CI [0.17, 0.82], p = 0.012). However, this effect disappeared in LRP patients (see Supplementary Table 1).