lee qz, nik ritza k, mohd firdaus ca, muhammad m.  (2023).  the impact of laparoscopic intraperitoneal instillation of ropivacaine in enhancing respiratory recovery and reducing acute postoperative pain in laparoscopic sleeve gastrectomy: a double-blinded randomised control; relieve trial.  - obesity surgery.  3141-3146. 

asif sukri, alfizah hanafiah, nik ritza kosai, mustafa mohammed taher, ramelah mohamed.  (2022).  new insight on the role of helicobacter pylori caga in the expression of cell surface antigens with important biological functions in gastric carcinogenesis.  - helicobacter.  1-8. 

syarifah nafisah al-yahya, muhammad haffiz haslam mohamed akram, kasturi vijaya kumar, siti nor asyrah mat amin, noor alifah abdul malik, nor ain mohd zawawi, nik ritza kosai nik mahmood,norlaila mustafa, mawaddah azman, and marina mat baki.  (2022).  maximum phonation time normative values among malaysians and its relation to body mass index.  - journal of voice.  457-463. 

wah-kheong chan, soek-siam tan, siew-pheng chan, yeong-yeh lee, hoi-poh tee, sanjiv m., khean-lee goh, anis safura ramli, feisul m., nik ritza k. dan raja affendi ra.  (2022).  malaysian society of gastroenterology and hepatology consensus statement on metabolic dysfunction-associated fatty liver disease.  - gastroenterology and hepatology.  795-811. 

masayuki o, soo min a, yosuke s, wah y, simon kin hw, suthep u, jefrey m. h, manish k, nik ritza k, weu w, june l, reno r, thejana w, edward o.  (2022).  ten years of change in bariatric/metabolic surgery in the asia-pacific region with covid-19 pandemic: ifso-apc national reports 2021.  - obesity surgery.  2994-3004. 

nur izreena ismail, raja affendi raja ali, zhiqin wong, khairul najmi muhammad nawawi, wei hao kok, nik ritza kosai nik mahmood, chia hsin chew, chong chearn lee, azmi mohd tamil, hazel joseph.  (2022).  the effect of lactobacillus reuteri probiotic as an adjunct treatment for helicobacter pylori infection in adults.  - gut.  1. 

nik ritza kosai, raja affendi raja ali.  (2022).  global multi-stakeholder endorsement of the mafld definition.  - the lancet gastroenterology and hepatology.  388-390. 

asif sukri, alfizah hanafiah, and nik ritza kosai.  (2022).  the roles of immune cells in gastric cancer: anti-cancer or pro-cancer?.  - cancers.  1-14. 

raymond zml, hans am, malaysian upper gastrointestinal surgical society (mugis), ng cb, low ky, sekkapan t, ngo cw, nik ritza kosai, reynu r, mohamad as, ahmad sudiman ms, ramesh g, azrina ab, mahadevan dt, vijaya sa, wan najmi wd, lim sy, kelvin v, moha.  (2022).  esophageal squamous cell carcinoma and adenocarcinoma in malaysia - pooled data from upper gastrointestinal centers in a multiethnic asian population.  - cancer epidemiology.  1-8. 

zahra rashidbenam, mohd hafidzul jasman, guan hee tan, eng hong goh, xeng inn fam, christopher chee kong ho, zulkifli md zainuddin, reynu rajan, rizal abdul rani, fatimah mohd nor, mohamad aznan shuhaili, nik ritza kosai, farrah hani imran, min hwei ng.  (2021).  fabrication of adipose-derived stem cell-based self-assembled scaffold under hypoxia and mechanical stimulation for urethral tissue engineering.  - international journal of molecular sciences.  1-32. 

asif sukri, alfizah hanafiah, noraziah mohamad zin, nik ritza kosai.  (2020).  epidemiology and role of helicobacter pylori virulence factors in gastric cancer carcinogenesis.  - apmis.  150-161. 

surita binti said, guo hou loo, nik ritza kosai, reynu rajan, rozita mohd, asrul abdul wahab, shamsul azhar shah.  (2020).  reduction in urinary chemokine (c-c motif) ligand 2 (ccl-2) after surgery-induced weight loss.  - scientific reports.  1-6. 

jimmy bys, jiafu j, sang uk, masanori t, guoxin li, hh kim, simon l, asim s, kyo ys, woo jh, nik ritza kosai, koji k, kazunari m, hiroshi y, takahiro k, peng cl, young wk, jaideeraj r, bee ct, hk yang, expel study group.  (2020).  extensive peritoneal lavage after curative gastrectomy for gastric cancer study (expel): an international multicenter randomized controlled trial.  - journal of clinical oncology.  279. 

loo guo hou, reynu rajan, azmi mohd tamil, nik ritza kosai.  (2020).  prevalence of obstructive sleep apnea in asian bariatric population: an underdiagnosed dilemma.  - surgery for obesity and related disease.  778-783. 

sivaneswaran lechmiannandan, mayurran panirselvam, prema muninathan, narwani hussin, reynu rajan, hatta sidi, nik ritza kosai & c. rajkumar vinayak.  (2019).  resolution of female sexual dysfunction (fsd) among the obese multiethnic malaysian women now a reality with bariatric surgery: a prospective pilot study in malaysia.  - obesity surgery.  1571-1575. 

globalsurg collaborative; dayang nita abdul aziz, reynu rajan, mohammed taher, nik ritza kosai.  (2019).  pooled analysis of who surgical safety checklist use and mortality after emergency laparotomy.  - british journal of surgery.  103-112. 

kavitha subramaniam, wah-yun low, peng-choong lau, kin-fah chin, karuthan chinna, nik ritza kosai, mustafa mohammed taher, and reynu rajan.  (2018).  eating behaviour predicts weight loss six months after bariatric surgery: a longitudinal study.  - nutrients.  1-13. 

mustafa mohammed taher, nik ritza kosai, dayang nita abdul aziz, reynu rajan.  (2018).  surgical site infection after gastrointestinal surgery in high-income, middle-income and low-income countries: a prospective, international, multicentre cohort study.  - lancet infectious disease.  . 

reynu rajan, nik ritza kosai.  (2018).  history and progress of bariatric surgery in malaysia.  - obesity surgery.  . 

globalsurg collaborative, dayang nita abdul aziz, mustafa mohamed, reynu rajan, nik ritza kosai..  (2018).  management and outcomes following surgery for gastrointestinal typhoid: an international, prospective, multicentre cohort study.  - world journal of surgery.  . 

globalsurg collaborative, nik ritza kosai, mustafa taher, reynu rajan.  (2018).  laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.  - surgical endoscopy.  . 

w. liew, y. y. wai, n. r. kosai, h. s. gendeh.  (2017).  tackers versus glue mesh fixation: an objective assessment of postoperative acute and chronic pain using inflammatory markers.  - hernia.  549-554. 

zar chi thent, chiranjib chakraborty, pasuk mahakkanukrauh, nik ritza kosai nik mahmood, reynu rajan and srijit das.  (2017).  the molecular concept of atheromatous plaques.  - current drug targets.  1250-1258. 

elsa jr, reynu r, kosai nr.  (2016).  the effect of laparoscopic bariatric surgery on serum fibrinogen level : a prospective study in obese malaysian population.  - obesity surgery (ifso).  552-553. 

mohd firdaus ca, reynu r, kosai nr.  (2016).  the effect of crura reinforcement on gastro-oesophageal reflux disease score following laparoscopic sleeve gastrectomy; a randomised controlled trial.  - obesity surgery (ifso).  550-551. 

shabbir a, bc tai, lakdawala m, huang ck, praveen raj p, sby jimmy, eng a, lomanto d, cheng ak, rao j, rajan r, delko t, kosai n, k kasama, kow l, wei-jei lee.  (2016).  influence of asian ethnicity on weight loss 3 years following laparoscopic sleeve gastrectomy.  - obesity surgery (ifso).  349. 

reynu r, hilal z, kosai nr.  (2016).  early effect of bariatric surgery on serum renin-aldosterone, blood pressure and weight: a prospective study in obese malaysian population.  - obesity surgery (ifso).  282-283. 

reynu r, hisham ahk, kosai nr.  (2016).  concurrent minimally invasive repair of ventral hernia during laparoscopic sleeve gastrectomy : a prospective study.  - obesity surgery (ifso).  251. 

m mohd sukri, a hanafiah, n nik mahmood, mmohamed taher, i mohamed rose, r mohamed.  (2016).  distribution of cd antigens in gastric adenocarcinoma cell line infected with different caga genotypes of helicobacter pylori strains.  - helicobacter.  115-116. 

reynu r, zainal za, kosai nr.  (2016).  pre-operative methods to reduce liver volume:a randomised controlled trial comparing the use of omega-3polyunsaturated fatty acid supplements vs vlcd restriction in patients awaiting bariatric surgery.  - obesity surgery.  122-123. 

asif sukri, alfizah hanafiah, nik ritza kosai, mustafa mohamed taher and isa mohamed rose.  (2016).  surface antigen profiling of helicobacter pylori-infected and -uninfected gastric cancer cells using antibody microarray.  - helicobacter.  417-427. 

a. bhangu, ......, nr kosai, m taher, r rajan.....globalsurg collaborative.  (2016).  mortality of emergency abdominal surgery in high-, middle- and low-income countries.  - british journal of surgery.  971-988. 

r reynu, nr kosai, mt mustafa, lakdawala ma.  (2015).  concurrent laparoscopic mesh repair of a morgagni hernia, umbilical hernia and sleeve gastrectomy in a morbidly obese individual.  - obesity surgery (ifso).  322-323. 

nr kosai, r reynu, at hizami, g tikfu.  (2015).  comparative study between laparoscopic sleeve gastrectomy and laparoscopic banded gastric plication in malaysia.  - obesity surgery (ifso).  324. 

kosai nr, levin kb, reynu r, taher mm, ali rar, palaniappan s.  (2015).  snapshot quiz 15/1 (small bowel adenocarcinoma in crohn`s disease).  - british journal of surgery.  4-15. 

r reynu, nr kosai, a haniffa.  (2015).  predicting diabetes remission following laparoscopic bariatric surgery in morbid obesity: a malaysian experience.  - obesity surgery (ifso).  323-324. 

razman jarmin, zamri zuhdi, hairol othman, yussra yusoff, affirul chairil ariffin, razrim rahim, azlanuddin azman, nik ritza nik kosai.  (2014).  the management of acute cholecystitis in pregnancy.  - hpb journal.  340. 

r jarmin, z zuhdi, a azman, y yusoff, ac ariffin, nrn kosai, h othman, r rahim.  (2014).  early experience of the lateral approach for laparoscopic splenic preserving distal pancreatectomy.  - hpb ( journal of internation hepato-pancreatico-biliary association).  642. 

thu, y; barakatun nisak, m; chin, y; gee, t; rohana, a; nik, r.  (2014).  comparison study between bariatric surgery and conventional treatment on nutritional status and quality of life among morbidly obese malaysian patients.  - obesity reviews.  15(S2):135.