The Influence of Urate-lowering Therapy on Sperm Quality of Male Gouty Patients：A Prospective Cohort Study

1. Research drugs. Three kinds of uric acid lowering drugs, allopurinol, febuxostat and benzbromarone, will be evaluated in this study.
2. Study design and sample size calculation. This study was designed as a single-center prospective cohort study. After a careful search of the relevant literature, there are no reports of similar studies, so it is impossible to accurately estimate the sample size. Therefore, this study planned to enroll 20 patients with gout who were using allopurinol, febuxostat and benzbromarone to reduce uric acid, respectively. It is planned to recruit 5 gouty patients and 5 control males every month. Therefore, the whole study needs to last at least 12 months after initiation
3. Research process. The process of this study does not affect the routine diagnosis and treatment procedures of patients with gout. Our research team is made up of doctors majoring in rheumatology and andrology. Therefore, we can make routine clinical diagnosis and treatment according to the specific conditions of patients with gout.
4. Screening period. It will takes about 2 weeks, including the following forms:
5. Patients with gout are in acute attack. According to the guidelines for the diagnosis and treatment of gout, we should first give them anti-inflammatory and analgesic treatment. Non-steroidal anti-inflammatory drugs(NSAIDs) or colchicine can be selected to control acute symptoms. Then we performed the semen analysis after the joint swelling and pain is completely improved. If the patient meets our admission criteria, urate-lowering therapy should be initiated according to the clinical practice. And we regard this time as week 0. NSAIDs or colchicine can be prophylacticly used for at least 2 weeks combined with urate-lowering treatment in case of gout flare.
6. Patients with gout in remission. For this kind of patients, we directly conduct semen analysis. If the results meets our admission criteria, urate-lowering therapy should be initiated according to the clinical practice. We also regard this time as week 0. And the preventive use of NSAIDs or colchicine is the same as above.
7. Follow-up stage. The follow-up cycle was calculated after the beginning of urate-lowering therapy. We will detect the blood routine, urine routine, liver and kidney function and serum uric acid at the time of screening and week 2, week 4, week 8 and week 12 visits. The patients will receive the repeated sperm analysis at week 4 and week 12, respectively. At the same time, we will collect all the corresponding data on the case report form. 4、Patient withdrawal. Patients can drop out of the trial at any time. Researchers can also persuade patients to withdraw for a variety of reasons, including baseline screening for sperm quality below World Health Organization (WHO) standards, adverse events, safety concerns, or patients' failure to comply with the trial regimen. 5、Eliminated cases. For some reason, those who are not completed as planned and whose observation records are incomplete are eliminated cases. Those who are interrupted due to serious adverse reactions should be regarded as cases of adverse reactions and shall not be included in the statistics of comparative analysis of semen. 6、Treatment regimen. Baseline screening: if the patient meets the selection criteria and is not in the gout attack period, we can consider the direct start of uric acid-lowering drug treatment. The choice of uric acid-lowering drugs should be based on the patient's drug use taboos for real-world choice. If the patient is in the attack stage of acute arthritis, we need to control the acute symptoms, and we can consider using NSAIDs, and then start the uric acid treatment after the joint symptoms are completely improved.

Uric acid-lowering therapy: the beginning of uric acid-lowering therapy must be combined with NSAIDs or colchicine to prevent gout.

• Allopurinol, the initial dose of 125mg once a day. If serum uric acid is not less than 360 µm/L after 4 weeks, the dose can be increased to 250mg once a day, and the highest dose does not exceed 500mg every day.
• Febuxostat, the initial dose of 20mg once a day. If serum uric acid is not less than 360 µm/L after 4 weeks, the dose can be increased to 40mg once a day, and the highest dose does not exceed 80mg every day.
• Benzbromarone, the initial dose of 25mg once a day. If serum uric acid is not less than 360 µm/L after 4 weeks, the dose can be increased to 50mg once a day, and the highest dose does not exceed 100mg every day. 7、Assessment. We will use two methods to assess male fertility: basic semen analysis and sperm DNA integrity analysis.

1. Basic semen analysis and sperm DNA fragmentation were performed at Reproductive Medicine Centre, Peking University Third Hospital using standard laboratory procedures, per WHO guidelines (2010 5th edition). This is a microscopic evaluation of fresh semen that assesses sperm concentration, viability, motility, and morphology.
2. Sperm Testing for DNA Fragmentation: The sperm DNA fragmentation assay was utilized to assess sperm DNA integrity based upon the literature report (Cytometry 1985; 6(3): 238-53) in which sperm DNA is stained with acridine orange and analyzed by flow cytometry.Two measurements are then produced: %DFI (DNA fragmentation index) which indicates level of sperm DNA breaks and %HDS (high DNA stainability) which is reported to correlate to levels of immature sperm and somatic cells such as white blood cells.
3. Serum samples for the analysis of serum uric acid were collected at the time of screening, week 4, week 8 and week 12, or early termination. 8、Samples collection, preservation and destruction
4. Semen samples were collected by masturbation after an instructed period of 2 to 3 days without ejaculation in the semen collection room of Peking University third Hospital after signing the informed consent according to the trial scheme. After semen liquefaction (30 minutes to 1 hour), an aliquot was used for semen analysis and a second aliquot of raw semen was frozen within 2 hours of collection at -80° C.
5. Semen samples are uniformly preserved until destroyed after the end of this trial. The test time is expected to be 2-3 years.
6. At the end of the trial, the semen samples were uniformly destroyed. The frozen semen was reheated at room temperature and completely soaked in 0.5% sodium hypochlorite disinfectant. Finally, the disinfection solution containing semen was treated as medical waste. 9、Quality control.
7. Carry out publicity and education to the subjects to reduce the rate of loss of follow-up; b. Semen quality analysis system was used to detect semen quality indexes such as sperm density, motility, forward motility ratio and so on. Quality control of standard samples was carried out for every 10 samples tested. 10、Statistical analysis. We will use SPSS 20.0 software for statistical analysis. All statistical tests are bilateral test, P value less than or equal to 0.05 will be considered to be statistically significant. When comparing the difference of curative effect between the parameters before and after gout treatment, paired t-test was used if the measurement data were in accordance with normal distribution. Independent sample t-test was used for comparison among different intervention groups. Nonparametric test is used if the measurement data do not conform to the normal distribution. Chi-square test was used to compare the counting data between groups.