Between January 1 through March 5, 2021, a total of 354 participants began enrollment, and 191 (53.9%) completed all IMPOWER baseline assessment forms. This included 119 (62.3%) pediatric and 72 (37.7%) adult participants. Due to differences in reporting and history of disease between adults who reported a childhood diagnosis and adults who reported their diagnosis in adulthood, we excluded 13 adult participants who registered and self-reported a childhood diagnosis and treatment from main analyses (Data not shown, see Additional file 2, which provides a comparison of adults by age at diagnosis). Table 1 displays patient demographics by type of registrant, comparing pediatric registrants compared to adult registrants diagnosed at 20 years of age or older. Ten pediatric registrants were deceased at the time of registration. At the time of enrollment, the median age was 4.4 years (range 0–17.5) for pediatric registrants and 38.3 years (range 22.6–66.7) for adult registrants.

Among pediatric registrants, 57.1% were diagnosed with malrotation at less than one month of age (Table 1). Additionally, 18.4% were diagnosed after one month of age but less than one year. Nearly 90% had symptoms before diagnosis, with vomiting or excessive spit-up, lethargy/weakness, and abdominal pain most commonly reported. Only 46.2% reported green bilious emesis before diagnosis, while 58.8% reported yellow bilious emesis before diagnosis, and 43.7% reported yellow-tinted spit up as a newborn while in the hospital shortly after birth. Around 70% reported volvulus at diagnosis.

Pediatric registrants reported frequent healthcare visits before diagnosis, which included frequent pediatrician visits (44.5%) and emergency department visits (35.3%) (Table 2). When examining test procedures leading up to diagnosis, 73.9% of pediatric registrants received an upper gastrointestinal series (UGI) with or without a small bowel follow-through, while only half reported that the UGI confirmed the diagnosis. Close to 20% were confirmed at the time of surgery or autopsy. The confirmatory test was most often made by an emergency department clinician (27.7%) followed by a surgeon (18.5%). When assessing the treatment of intestinal malrotation, 89.9% of pediatric registrants reported undergoing a surgical procedure for malrotation and/or volvulus.

The majority of initial surgical procedures were reported as emergent to preserve life (Table 3). Approximately one-third underwent a bowel resection as part of their initial surgical procedure for malrotation, and 23.4% were diagnosed with short bowel syndrome following the initial surgical procedure. Surgical complications were reported by 15.9% of pediatric participants immediately following their initial surgical procedure. Within the first year of the initial surgical procedure, almost half of pediatric registrants had subsequent emergency department visits, and a third had additional hospitalizations. Approximately a quarter had additional surgical procedures within the first year, with 8.4% reporting three or more additional surgical procedures.

When examining ongoing gastrointestinal symptoms following the initial surgical procedure, 62.6% of pediatric registrants reported gastrointestinal symptoms that persisted throughout the first year (Table 4). The most commonly reported symptoms were vomiting followed by difficulty tolerating foods, with each symptom reported in at least 20% of patients. Approximately 15% and 26% of pediatric registrants reported either the same or greater symptom severity or frequency after surgery, respectively. In the first year after the initial surgical procedure, 69.2% of pediatric patients visited at least one gastroenterologist, with 17% reporting visiting four or more gastroenterologists. Over 40% of patients visited a nutritionist/dietitian. At the time of registration, over a quarter of pediatric registrants were currently using medications (i.e., laxatives, antidiarrheal, motility, and pain medications), and a similar proportion utilized dietary changes to manage gastrointestinal symptoms.

Among adult registrants aged 20 years or older at the time of reported diagnosis, 98.2% experienced symptoms before diagnosis (Table 1). Abdominal pain was overwhelmingly the most commonly reported symptom, along with constipation and swollen abdomen. Intermittent abdominal pain was the most prevalent (76.4%). Like pediatric registrants, adults were more likely to report yellow bilious emesis (43.6%) than green bilious emesis (21.8%). Adult registrants were likely to report frequent emergency department visits, specialty care visits, and primary care visits before diagnosis, and the confirmatory test for adults was most often a computed tomography (CT) (69.1%) ordered by a gastroenterologist or emergency department clinician (Table 2). Slightly lower than for pediatric patients, 81.8% of adult registrants reported undergoing a surgical procedure for malrotation.

Adult registrants most often reported the surgical procedure to be recommended within the next month (40.0%) or considered elective (20.0%) (Table 3). Surgical complications were reported by 28.9% of adult participants immediately following their initial surgical procedure. A third had additional surgical procedures within the first year, with 8.9% reporting three or more additional surgical procedures.

Over 80% of adults reported gastrointestinal symptoms that persisted throughout the first year following their initial surgical procedure (Table 4). The most commonly reported symptoms for adult participants were abdominal pain followed by constipation and difficulty tolerating foods. Over half of adults reported their symptoms to be more or just as severe or frequent as before surgery. In the first year after the initial surgical procedure, 82.2% of adult patients visited at least one gastroenterologist, and 35.6% reported visiting four or more gastroenterologists.