Nocturia is the complaint of having to get up one or more times to urinate, after going to bed. In an international epidemiological survey, nocturia is a frequent lower urinary tract symptom that accounts for about half of those with nocturia symptoms regardless of gender or race. Nocturia affects both physical and mental health, is associated with death in patients over 60 years of age and impairs quality of life (QOL). In current medicine, it is difficult to alleviate nocturia symptoms with medication alone and the development of care to accompany medication is an urgent issue.
One of the causes of nocturia is increased venous return in the lower extremities at bedtime and it is said that wearing compression knee-high socks during the day is an effective treatment. However, currently, there are no comparative studies between the effects of compression knee-high socks and regular knee-high socks.
Therefore, the purpose of this study is to determine, for the first time, the effect of wearing compression knee-high socks versus regular knee-high socks during the day in participants with nocturia symptoms

This study is a randomized, double-blind, controlled trial, parallel group study.
After approval by the Ethics Committee and a pretest, the study was conducted from December 2021 to March 2022 and followed the Consolidated Standards of Reporting Trials (CONSORT) reporting guideline.
Study participants were people aged 40-79 years who have nocturia and who were recruited from among the 300,000 members of a Japanese own web-based travel agency with a large proportion of senior citizen members.
Participants were stratified and randomized by age, gender, and pre-existing disease using a random number table by the web-based company. Using the double-blind method, participants were divided into two groups: the intervention group wore commercially available compression knee-high socks and the control group wore regular knee-high socks made of the same material as the intervention group (both made in Japan).
The compression knee-high socks worn by the intervention group were made of 32.7% cotton, 20.7% rayon, 20.7% nylon, 20.7% polyurethane, 4% ester, and 1.2% other materials, with compression values of 23.8 hPa at the sole, 17.2 hPa at the ankle, and 10.4 hPa at the calf.
The regular knee-high socks worn by the control group were made of 34.7% cotton, 27.2% rayon, 24.5% ester, 7.7% polyurethane, and 5.9% other materials, with compression values of 6.9 hPa at the sole, 5.0 hPa at the ankle, and 4.6 hPa at the calf.
The study was conducted for a total of 21 days, including a 7-day pre-observation period, the 3 days from day 5 to 7, during which the participants became accustomed to the study, were used as the baseline. Participants wore each pair of knee-high socks (washed daily) for at least 8 hours per day from morning to evening. The survey consisted of participants answering five questions, including the number of times they urinated at night, every day for 21 days. They also responded to the Japanese version of N-QOL at the baseline after 14 days of wearing the knee-high socks. Participants were given a double-blind telephone survey by the web company if they were unable to respond online. After the survey, all the knee-high socks were collected, and their condition of use and the presence of defects were verified by an expert.
Statistical sample sizes were calculated. The number of participants allowed adequate assessment of the effects of wearing knee-high socks. All study data was listed, summarized and plotted.
After confirming the normality of the percent change from baseline for the intervention and control groups, a t-test with a two-group correspondence was used. A welch t-test was used for the difference between the two groups in the frequency of nocturnal urination and the total points of the Japanese version of N-QOL. SPSS version 28 was used. (Statistical power 80 %, P < .05)

During the 14 days of recruitment, 2803 people visited the website. Of these, 637 were registered as participants. Excepting exclusion factors, statistical sample size calculations were conducted, and the 170 participants were distributed evenly across Japan. The purpose and methods of the study were explained to them via the Web and by phone, and their consent was obtained. Excluding two dropouts, 168 participants were included in the analysis.
There was no significant difference between the two groups: the intervention group consisted of 85 participants (54 women) with a mean age of 58.1 (±9.6) years and BMI of 22.8 (±2.7), and the control group consisted of 83 participants (51 women) with a mean age of 60.2 (±8.4) years and BMI of 23.3 (±2.9).
The mean frequency of nocturnal urination at baseline was 2.22 (±0.79) in the intervention group and 2.29 (±0.73) in the control- group, with no significant difference.
The mean frequency of nocturnal urination for the 3 days prior to the 12th-14th day of wearing the knee-high socks was 1.55 (±0.53) times in the intervention group and 1.73 (±0.67) times in the control group, with a significant decrease in urination frequency for the compression knee-high socks (P=.03).
The mean frequency of nocturnal urination for the 3 days prior to the 12th-14th day of wearing the knee-high socks was 2.22 (±0.79) times and 1.55 (±0.53) times in the intervention group, a significant decrease in frequency. (P<.001) Nocturnal urination frequency in the control group also significantly decreased from 2.29 (±0.73) times and 1.73 (±0.67) times. (P<.001)
The mean frequency of nocturnal urination for the 3 days prior to the 1st-3th day of wearing the knee-high socks was 1.94 (±0.75) times in the intervention group (P<.001) and 1.91 (±0.88) times in the control group (P=.03) with a significantly reduced compared to the baseline.
The total points for the Japanese version of N-QOL was 50.9 (±6.4) for the intervention group and 50.3 (±7.0) for the control group at baseline, which was not significant. The total points after 14 days of wearing knee-high socks was 64.9 (±7.1) for the intervention group and 63.2 (±2.3) for the control group. Although there was no difference in quality of life between the two groups (P=.82), both groups significantly improved their quality of life by wearing knee-high socks. (P<.001). 
Participants had no adverse events from wearing the knee-high socks and wished to continue wearing them.

Nocturia symptoms were found to decrease the frequency of urination at night on days when knee-high socks were worn during the day. In addition, wearing compression knee-high socks increased venous return in the lower extremities during the day, suggesting that these socks were more effective than regular knee-high socks in decreasing nocturnal urinary frequency.
Since nocturia decreases QOL, a decrease in urination frequency significantly improves QOL. Therefore, wearing more effective compression knee-high socks is desirable. However, this study suggests that those who have difficulty wearing compression knee-high socks, may not have to give up but may instead be able to choose knee-high socks according to their preferences and circumstances.

For nocturia symptoms, wearing knee-high socks for 8 hours or more during the daytime decreased nocturnal urination frequency and improved quality of life, suggesting that compression knee-high socks were more effective in decreasing nocturnal urination frequency than regular knee-high socks.

Continence 2S2 (2022) 100329
DOI: 10.1016/j.cont.2022.100329