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Dive into the research topics where Dong Hyuk Kang is active.

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Featured researches published by Dong Hyuk Kang.


Korean Journal of Urology | 2013

Impact of Surgical Varicocele Repair on Pregnancy Rate in Subfertile Men With Clinical Varicocele and Impaired Semen Quality: A Meta-Analysis of Randomized Clinical Trials

Kyu Hyun Kim; Joo Yong Lee; Dong Hyuk Kang; Hyungmin Lee; Ju Tae Seo; Kang Su Cho

Purpose To elucidate the impact of surgical varicocele repair on the pregnancy rate through new meta-analyses of randomized clinical trials that compared surgical varicocele repair and observation. Materials and Methods The PubMed and Embase online databases were searched for studies released before December 2012. References were manually reviewed, and two researchers independently extracted the data. To assess the quality of the studies, the Cochrane risk of bias as a quality assessment tool for randomized controlled trials was applied. Results Seven randomized clinical trials were included in our meta-analyses, all of which compared pregnancy outcomes between surgical varicocele repair and control. There were differences in enrollment criteria among the studies. Four studies included patients with clinical varicocele, but three studies enrolled patients with subclinical varicocele. Meanwhile, four trials enrolled patients with impaired semen quality only, but the other three trials did not. In a meta-analysis of all seven trials, a forest plot using the random-effects model showed an odds ratio (OR) of 1.90 (95% confidence interval [CI], 0.77 to 4.66; p=0.1621). However, for subanalysis of three studies that included patients with clinical varicocele and abnormal semen parameters, the fixed-effects pooled OR was significant (OR, 4.15; 95% CI, 2.31 to 7.45; p<0.001), favoring varicocelectomy. Conclusions Varicocelectomy for male subfertility is proven effective in men with clinical varicocele and impaired semen quality. Therefore, surgical repair should be offered as the first-line treatment of clinical varicocele in subfertile men.


The Journal of Urology | 2013

Safety and Efficacy of Once Daily Administration of 50 mg Mirodenafil in Patients with Erectile Dysfunction: a Multicenter, Double-Blind, Placebo Controlled Trial

Jae Hoon Chung; Dong Hyuk Kang; Cheol Young Oh; Jae Min Chung; Ki Soo Lee; Tae Hyo Kim; Kyung Hyun Moon; Wan Lee; Jeong Man Cho; Seung Wook Lee

PURPOSE We evaluated the improvement in erectile dysfunction and lower urinary tract symptoms as well as the safety of once daily administration of 50 mg mirodenafil in men with erectile dysfunction. MATERIALS AND METHODS A total of 226 patients visited for treatment of erectile dysfunction and were recruited for the study. Of these men 180 met the study inclusion criteria after completing a 2-week screening period (visit [V]1). The patients were randomly allocated into 2 groups. Group 1 (90 patients) received 50 mg mirodenafil once daily and group 2 (90 patients) received a placebo daily. Blood pressure, heart rate, IIEF-5 (5-item version of the International Index of Erectile Function), and SEP (Sexual Encounter Profile) questions 2 and 3 were assessed at 4 (V2), 8 (V3) and 12 weeks after the start of treatment (V4). I-PSS (International Prostate Symptom Score), maximal flow rate and post-void residual volume were also assessed for the evaluation of lower urinary tract symptoms. RESULTS Of the 180 patients 71 in group 1 and 63 in group 2 completed the 12-week clinical trial. IIEF-5 and I-PSS significantly improved in group 1 (p <0.001 for both). Facial flushing was the most common adverse effect, followed by headaches. Notably there were no statistically significant differences in either of the variables related to the cardiovascular system. CONCLUSIONS Once daily administration of 50 mg mirodenafil was efficacious and safe for the treatment of erectile dysfunction and lower urinary tract symptoms.


Journal of Endourology | 2013

The Effects of Hyaluronic Acid and Carboxymethylcellulose in Preventing Recurrence of Urethral Stricture After Endoscopic Internal Urethrotomy: A Multicenter, Randomized Controlled, Single-Blinded Study

Jae Hoon Chung; Dong Hyuk Kang; Hong Yong Choi; Tae Yoong Jeong; U-Syn Ha; Jun Hyun Han; Ji Hyeong Yu; Jeong Man Cho; Tag Keun Yoo; Jinsung Park; Tae Hyo Kim; Seung Wook Lee

BACKGROUND To evaluate the effects of hyaluronic acid (HA) and carboxymethylcellulose (CMC) on the recurrence of urethral stricture after treatment with endoscopic internal urethrotomy (EIU). METHODS A total of 120 patients underwent EIU for urethral stricture. Recruited patients were randomly divided into two groups: group A and B. Patients in group A (60 patients, experimental group) received HA/CMC instillation and patients in group B (60 patients, control group) received lubricant instillation after internal urethrotomy. Each patient was evaluated at 4 weeks (V1), 12 weeks (V2), and 24 weeks (V3) after the surgery. The effectiveness of HA/CMC instillation was evaluated based on the International Prostate Symptom Score/Quality of Life, peak urine flow rate, voided volume and postvoiding residual urine volume. The visual analogue scale (VAS) pain score and degree of satisfaction were also determined for each participant. RESULTS Among 120 initial participants, 53 patients in group A and 48 patients in group B had completed the experiment. VAS pain scores were 0.67±0.76 and 3.60±1.52 (p<0.001), and degrees of satisfaction were 0.28±0.50 and 0.80±0.81 in group A and group B at 1 month after surgery (p=0.001). The recurrence of urethral stricture was observed in five cases (9.4%) in group A and 11 (22.9%) in group B (p=0.029). CONCLUSIONS HA/CMC instillation during EIU may decrease the incidence of urethral stricture recurrence. In addition, the use of HA/CMC was effective in reducing pain during the early postoperative period without an adverse effect.


Scientific Reports | 2016

Stone heterogeneity index as the standard deviation of Hounsfield units: A novel predictor for shock-wave lithotripsy outcomes in ureter calculi

Joo Yong Lee; Jae Heon Kim; Dong Hyuk Kang; Doo Yong Chung; Dae Hun Lee; Hae Do Jung; Jong Kyou Kwon; Kang Su Cho

We investigated whether stone heterogeneity index (SHI), which a proxy of such variations, was defined as the standard deviation of a Hounsfield unit (HU) on non-contrast computed tomography (NCCT), can be a novel predictor for shock-wave lithotripsy (SWL) outcomes in patients with ureteral stones. Medical records were obtained from the consecutive database of 1,519 patients who underwent the first session of SWL for urinary stones between 2005 and 2013. Ultimately, 604 patients with radiopaque ureteral stones were eligible for this study. Stone related variables including stone size, mean stone density (MSD), skin-to-stone distance, and SHI were obtained on NCCT. Patients were classified into the low and high SHI groups using mean SHI and compared. One-session success rate in the high SHI group was better than in the low SHI group (74.3% vs. 63.9%, P = 0.008). Multivariate logistic regression analyses revealed that smaller stone size (OR 0.889, 95% CI: 0.841–0.937, P < 0.001), lower MSD (OR 0.995, 95% CI: 0.994–0.996, P < 0.001), and higher SHI (OR 1.011, 95% CI: 1.008–1.014, P < 0.001) were independent predictors of one-session success. The radiologic heterogeneity of urinary stones or SHI was an independent predictor for SWL success in patients with ureteral calculi and a useful clinical parameter for stone fragility.


Korean Journal of Urology | 2010

Efficacy and Safety of Tadalafil 5 mg Administered Once Daily in Korean Men with Erectile Dysfunction: A Prospective, Multicenter Study.

Dong Hyuk Kang; Joo Yong Lee; Sung Yul Park; Hong Sang Moon; Tae Yoong Jeong; Tag Keun Yoo; Hong Yong Choi; Hae Young Park; Tchun Yong Lee; Seung Wook Lee

Purpose The aim of this study was to evaluate the efficacy of a daily dose of tadalafil 5 mg as well as its safety for the cardiovascular system in men with erectile dysfunction. Materials and Methods This study included a total of 162 men who were administered a daily dose of tadalafil 5 mg between April and December of 2009. A total of 127 men completed the 8-week clinical trial. The International Index of Erectile Function (IIEF)-5, blood pressure, and heart rate were measured before treatment with tadalafil (V1) and 4 (V2) and 8 weeks (V3) after treatment with tadalafil. Adverse effects were assessed at V1, V2, and V3. In cases in which the International Prostate Symptom Score (IPSS) was ≥8 at V1, maximal flow rate (Qmax) and postvoid residual volume (PVR) were measured. Results The IIEF-5 values were 11.25±3.18, 14.56±3.79, and 16.91±3.56 at V1, V2, and V3, respectively, with significant improvement (V1 vs. V2, p<0.001; V1 vs. V3, p<0.001). The IPSS values were 10.59±5.56, 9.07±6.06, and 8.15±6.10 at V1, V2, and V3, respectively, and the differences were statistically significant (V1 vs. V2, p<0.001; V1 vs. V3, p<0.001). There were no significant differences in blood pressure or heart rate. Adverse effects were observed in 7 men (5.51%) at V2 and in 5 men (3.94%) at V3. Conclusions Tadalafil 5 mg administered once-a-day may be effective in improving erectile function. Adverse effects on the cardiovascular system may be minimal. In addition, it is believed that this may also be effective in improving voiding symptoms.


The World Journal of Men's Health | 2016

A Systematic Review and Meta-Analysis of Functional Outcomes and Complications Following the Photoselective Vaporization of the Prostate and Monopolar Transurethral Resection of the Prostate

Dong Hyuk Kang; Kang Su Cho; Won Sik Ham; Young Deuk Choi; Joo Yong Lee

Purpose To perform a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing monopolar transurethral resection of the prostate (MTURP) and photoselective vaporization of the prostate (PVP) in order to provide the most up-to-date and reliable recommendations possible. Materials and Methods Relevant RCTs were identified from electronic databases for meta-analysis of the surgical outcomes and complications of MTURP and PVP. Meta-analytical comparisons were made using qualitative and quantitative syntheses. The outcome variables are presented as odds ratios with 95% confidence intervals (CIs). Results In total, 11 articles were included in this comparative analysis of PVP versus MTURP. Most of the recently published studies exhibited low risk in terms of quality assessment. MTURP was superior to PVP regarding operative time; however, with regard to catheterization and hospitalization time, the mean differences were -1.39 (95% CI=-1.83~-0.95, p<0.001) and -2.21 (95% CI=-2.73~-1.69, p<0.001), respectively, in favor of PVP. PVP was superior to MTURP with regard to transfusion rate and clot retention, but no statistically significant differences were found with regard to acute urinary retention and urinary tract infection. The long-term complications of bladder neck contracture and urethral stricture showed no statistically significant differences between PVP and MTURP. Long-term functional outcomes, including the International Prostate Symptom Score and maximum flow rate, likewise did not display statistically significant differences between PVP and MTURP. Conclusions Based on our findings, we believe that PVP should be considered as an alternative surgical procedure for treating male lower urinary tract symptoms secondary to benign prostatic hyperplasia.


PLOS ONE | 2015

Impact of colic pain as a significant factor for predicting the stone free rate of one-session shock wave lithotripsy for treating ureter stones: a Bayesian logistic regression model analysis

Doo Yong Chung; Kang Su Cho; Dae Hun Lee; Jang Hee Han; Dong Hyuk Kang; Hae Do Jung; Jong Kyou Kown; Won Sik Ham; Young Deuk Choi; Joo Yong Lee

Purpose This study was conducted to evaluate colic pain as a prognostic pretreatment factor that can influence ureter stone clearance and to estimate the probability of stone-free status in shock wave lithotripsy (SWL) patients with a ureter stone. Materials and Methods We retrospectively reviewed the medical records of 1,418 patients who underwent their first SWL between 2005 and 2013. Among these patients, 551 had a ureter stone measuring 4–20 mm and were thus eligible for our analyses. The colic pain as the chief complaint was defined as either subjective flank pain during history taking and physical examination. Propensity-scores for established for colic pain was calculated for each patient using multivariate logistic regression based upon the following covariates: age, maximal stone length (MSL), and mean stone density (MSD). Each factor was evaluated as predictor for stone-free status by Bayesian and non-Bayesian logistic regression model. Results After propensity-score matching, 217 patients were extracted in each group from the total patient cohort. There were no statistical differences in variables used in propensity- score matching. One-session success and stone-free rate were also higher in the painful group (73.7% and 71.0%, respectively) than in the painless group (63.6% and 60.4%, respectively). In multivariate non-Bayesian and Bayesian logistic regression models, a painful stone, shorter MSL, and lower MSD were significant factors for one-session stone-free status in patients who underwent SWL. Conclusions Colic pain in patients with ureter calculi was one of the significant predicting factors including MSL and MSD for one-session stone-free status of SWL.


Investigative and Clinical Urology | 2016

Ureteral stenting can be a negative predictor for successful outcome following shock wave lithotripsy in patients with ureteral stones

Dong Hyuk Kang; Kang Su Cho; Won Sik Ham; Doo Yong Chung; Jong Kyou Kwon; Young Deuk Choi; Joo Yong Lee

Purpose To evaluate ureteral stenting as a negative predictive factor influencing ureteral stone clearance and to estimate the probability of one-session success in shock wave lithotripsy (SWL) patients with a ureteral stone. Materials and Methods We retrospectively reviewed the medical records of 1,651 patients who underwent their first SWL. Among these patients, 680 had a ureteral stone measuring 4–20 mm and were thus eligible for our study. The 57 patients who underwent ureteral stenting during SWL were identified. Maximal stone length (MSL), mean stone density (MSD), skin-to-stone distance (SSD), and stone heterogeneity index (SHI) were determined by pre-SWL noncontrast computed tomography. Results After propensity score matching, 399 patients were extracted from the total patient cohort. There were no significant differences between stenting and stentless groups after matching, except for a higher one-session success rate in the stentless group (78.6% vs. 49.1%, p=0.026). In multivariate analysis, shorter MSL, lower MSD, higher SHI, and absence of a stent were positive predictors for one-session success in patients who underwent SWL. Using cutoff values of MSL and MSD obtained from receiver operator curve analysis, in patients with a lower MSD (≤784 HU), the success rate was lower in those with a stent (61.1%) than in those without (83.5%) (p=0.001). However, in patients with a higher MSL (>10 mm), the success rate was lower in those with a stent (23.6%) than in those without (52.2%) (p=0.002). Conclusions Ureteral stenting during SWL was a negative predictor of one-session success in patients with a ureteral stone.


The Journal of Urology | 2013

Laparoendoscopic Single Site Varicocele Ligation: Comparison of Testicular Artery and Lymphatic Preservation Versus Complete Testicular Vessel Ligation

Dong Hyuk Kang; Joo Yong Lee; Jae Hoon Chung; Jung Ki Jo; Seung Hwan Lee; Won Sik Ham; Kang Su Cho; Ki Soo Lee; Tae Hyo Kim; Seung Wook Lee

PURPOSE We compared postoperative outcomes in patients treated with laparoendoscopic single site varicocele ligation with or without testicular artery and lymphatic preservation. MATERIALS AND METHODS A total of 80 patients with left varicocele were randomly divided into 2 groups and treated with laparoendoscopic single site varicocele ligation with preservation of the testicular artery and lymphatics (40 in group 1) or complete ligation of the testicular vessels and lymphatics (40 in group 2). Operative time, hospital stay, return to normal activity, postoperative visual analog scale pain scores and complications were analyzed. In patients with subfertility preoperative and 3-month postoperative semen analyses were performed. In patients with scrotal pain preoperative and 12-month postoperative visual analog scale pain scores were analyzed. RESULTS A total of 35 patients per group completed the study. Hospital stay, return to normal activity and postoperative pain scores did not differ between the groups. No major complications were observed. Mean ± SD operative time was 60.7 ± 10.7 and 48.6 ± 6.0 minutes in groups 1 and 2, respectively (p <0.001). Patients with subfertility, including 22 in group 1 and 21 in group 2, showed improved semen parameters 3 months postoperatively but postoperative values did not differ between the groups. The 17 patients in each group with scrotal pain showed decreased pain scores 12 months postoperatively with no difference between the groups. CONCLUSIONS Laparoendoscopic single site varicocele ligation is feasible. No differences in postoperative outcomes and complications were observed when preserving or not preserving the testicular artery and lymphatics.


Journal of Korean Medical Science | 2012

Assessing the quality of randomized controlled trials published in the Journal of Korean Medical Science from 1986 to 2011.

Jae Hoon Chung; Dong Hyuk Kang; Jung Ki Jo; Seung Wook Lee

Low quality clinical trials have a possibility to have errors in the process of deriving the results and therefore distort the study. Quality assessment of clinical trial is necessary in order to prevent any clinical application erroneous results is important. Randomized controlled trial (RCT) is a design for evaluate the effectiveness of medical procedure. This study was conducted by extracting the RCTs from the original articles published in the Journal of Korean Medical Science (JKMS) from 1986 to 2011 and conducting a qualitative analysis using three types of analysis tools: Jadad scale, van Tulder scale and Cochrane Collaboration risk of bias Tool. To compare the quality of articles of JKMS, quality analysis of the RCTs published in Yonsei Medical Journal (YMJ) and Korean Journal of Internal Medicine was also conducted. In the JKMS, YMJ and Korean Journal of Internal Medicine, the quantitative increase of RCT presented over time was observed but no qualitative improvement of RCT was observed over time. From the results of this study, it is required for the researchers to plan for and perform higher quality studies.

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