Formation of the Scandinavian Obesity Surgery Registry, SOReg.

BACKGROUND: Obesity surgery is expanding, the quality of care is ever more important, and learning curve assessment should be established. A large registry cohort can show long-term effects on obesity and its comorbidities, complications, and long-term side effects of surgery, as well as changes in health-related quality of life (QoL). Sweden is ideally suited to the task of data collection and audit, with universal use of personal identification numbers, nation-wide registries permitting cross-matching to analyze causes of death, in-hospital care, and health-related absenteeism. METHOD: In 2004, the Scandinavian Obesity Surgery Registry (SOReg) was initiated and government financing secured. A project group created a national database covering all public as well as private hospitals. Data entry was to be made online, operative definitions of comorbidity were formed, and complication severity scored. Several forms of audit were devised. RESULTS: After pilot studies, the system has been running in its present form since 2007. Since 15 January 2013, SOReg covers all bariatric surgery centers in Sweden. The number of operations in the database exceeded 40,000 (March 2014), with a median follow-up of 2.94 years. Audit shows that >98% of data are correct. All results are publicized annually on the Internet. COMMENTS: Using this systematic approach, it has been possible to cover >99% of all bariatric surgery, cross-matching our data with nation-wide registries for in-hospital care, cause of death, and permitting regular nation-wide audit. Several scientific studies have used, or are using, what seems to be the most comprehensive database in obesity surgery.

Body mass and reflux oesophagitis: an oestrogen-dependent association?

BACKGROUND: There is widespread belief that obesity is associated with gastro-oesophageal reflux disease, but the scientific evidence is weak and contradictory. Our aim is to evaluate the relation between body mass and reflux oesophagitis. METHODS: A population-based case-control study of endoscopically verified case subjects with reflux oesophagitis, and of randomly selected, control subjects matched for age, sex and area of residence. Subjects were classified within three body mass index (BMI) categories: BMI <25 (normal in the WHO classification), BMI 25-30 (overweight) and BMI >30 (obese). Odds ratios (OR) with 95% confidence intervals (CI) were the measures of association. RESULTS: Of 179 matched case-control pairs included in the study, 71 pairs were female. In males, no association between overweight and/or obesity and the risk of reflux oesophagitis was found. In females, there was a strong association between increasing BMI and the risk of reflux oesophagitis, with an OR of 2.9 (95% CI: 1.1-7.6) in the BMI 25-30 group and 14.6 (95% CI: 2.6-80.9) in the BMI >30 group (P value for trend = 0.0007). The association between obesity and oesophagitis was further strengthened by the use of oestrogen replacement medication. CONCLUSIONS: The study discloses a strong and dose-dependent association between body mass and reflux oesophagitis in women as opposed to no association among men. This association might be caused by increased oestrogen activity in overweight and obese females.

Prevention of peptic ulcer and dyspeptic symptoms with omeprazole in patients receiving continuous non-steroidal anti-inflammatory drug therapy. A Nordic multicentre study.

BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs) are known to cause gastroduodenal lesions and dyspeptic symptoms. METHODS: Patients with a history of dyspepsia or uncomplicated peptic ulcer disease and with a need for continuous NSAID treatment were randomized to receive either 20 mg omeprazole once daily or placebo. Gastroduodenal ulcers, erosions, and dyspeptic symptoms were evaluated after 1 and 3 months. RESULTS: During a 3-month study period 4.7% (4 of 85) of omeprazole-treated patients developed peptic ulcer, compared with 16.7% (15 of 90) of patients treated with placebo. This prophylactic effect of omeprazole was sustained independently of previous peptic ulcer history or Helicobacter pylori status. Development of dyspeptic symptoms requiring active treatment, either alone or in combination with ulcer(s) or erosions, occurred in 15.3% (15 of 85) of patients treated with omeprazole and 35.6% of those who received placebo. CONCLUSIONS: Omeprazole, 20 mg once daily, provides effective prophylactic therapy in patients at risk of developing NSAID-associated peptic ulcers or dyspeptic symptoms.

Risk of cancer following partial gastrectomy for benign ulcer disease.

The relative risk of developing cancer after partial gastrectomy for benign ulcer disease, expressed as the standardized incidence ratio, was examined in a population-based cohort comprising 6459 patients operated on between 1950 and 1958. Follow-up to 1983 revealed 1112 patients with cancer versus 1128 expected cases (relative risk 1.0 (95 per cent confidence interval (c.i.) 0.9-1.1)). The overall risk increased over time; it was higher in younger than in older patients but was not related to sex, surgical procedure (Billroth I or II gastrectomy) or diagnosis at operation (duodenal or stomach ulcer). There was an increased risk for lung cancer (relative risk 1.5 (95 per cent c.i. 1.2-1.7)), for oesophageal cancer in patients operated on for stomach ulcer (relative risk 2.2 (95 per cent c.i. 1.0-4.2)) and for cancer of the biliary tract in men (relative risk 1.9 (95 per cent c.i. 1.2-2.9)) and in those operated on for duodenal ulcer (relative risk 1.7 (95 per cent c.i. 1.0-2.8)). The overall risk for genital cancer in women was unchanged but decreased with increasing duration of follow-up and age. Cancers of the nervous system occurred less frequently than expected (relative risk 0.5 (95 per cent c.i. 0.3-0.8)), while the risk for cancer of the buccal cavity, lymphatic and haematopoietic systems, pancreas, breast, prostate, kidney and bladder was unchanged.

Gastric cancer risk after vagotomy.

The risk of gastric cancer after vagotomy for benign gastric and duodenal disease was examined in a population based cohort of 7198 patients operated on during 1971-79 and followed up until 1988. After exclusion of the first year of follow up there were 34 cases of gastric cancer compared with 25.6 expected (standardised incidence ratio (SIR) = 1.33; 95% confidence intervals (CI) 0.92 to 1.86). Separate analyses by duration of follow up, sex, age at operation, underlying diagnosis, and operative procedures did not show any significant increased or decreased risk of gastric cancer in any of the subgroups. In conclusion, decreased gastric acid secretion after vagotomy does not increase the risk of gastric cancer in the first 10 years after operation or in the subgroup followed up for 10-18 years. A longer follow-up is needed before an excess risk can be excluded.

Mortality among patients with partial gastrectomy for benign ulcer disease.

Partial gastrectomy for benign ulcer disease may influence future risk of death, eg, through changes in life-style or metabolism. To reveal such possible long-term effects, we analyzed a population-based cohort of 6459 patients operated on from 1950 through 1958 and followed through 1985. We found a lower overall mortality than in the general Swedish population (standardized mortality ratio = 0.94; 95% confidence interval 0.91-0.97). Mortality was decreased among those with duodenal ulcers, Billroth II operations, and older age at operation but increased as time passed after operation. Mortality was significantly (P < 0.05) increased from tuberculosis, alcoholism, emphysema, stomach ulcer, intestinal obstruction, gallbladder or biliary disease, suicide, and accidental falls but decreased from ischemic heart disease and cerebrovascular disease. Preoperative selection of healthy patients and the probable increased prevalence of risk factors for ulcer disease (smoking, alcoholism, and lower socioeconomic status) in this cohort explain most of these findings. Apart from intestinal obstruction, gallbladder or biliary tract diseases, and tuberculosis, the surgical procedure did not appear to increase mortality beyond one year after operation.

Intestinal and diffuse types of gastric cancer: secular trends in Sweden since 1951.

In order to test the hypothesis that the general decline in gastric cancer observed in many countries is due to a selective decline in Laurén's intestinal type, we re-examined all 427 histologic sections obtained from gastric carcinomas diagnosed at the Department of Pathology, University Hospital, Uppsala, Sweden, in 1951, 1961, 1971-72 and 1981. The relative proportions of intestinal and diffuse type cancers were compared. The intestinal type was significantly (P less than 0.001) more common among elderly people than in the younger age groups. The relative proportions of intestinal type carcinoma in the four periods under study were 65%, 55%, 42% and 60%, respectively. The absence of any clearly discernible trend over time contradicts the hypothesis of diverse secular trends for intestinal and diffuse types of gastric carcinoma.

Long-term survival in patients operated on for benign peptic ulcer disease.

Survival rate was analysed in a cohort of 6459 patients who had undergone partial gastrectomy for benign ulcer disease and who had survived the first year after operation. The cohort was followed for 27-35 years. There was a slight but significant decrease in relative survival rate to 92 per cent (95 per cent confidence interval 87-97 per cent) 35 years after operation. No decrease in relative survival rate was observed during the first 20 years after operation. There was no difference by gender or surgical procedure, but patients operated on for gastric ulcer, compared with duodenal ulcer, and patients operated on at younger ages had a poorer relative survival rate. The effects of partial gastrectomy on survival, both overall and by diagnosis or age at operation, are probably attributable to confounding factors linked with the peptic ulcer disease rather than to the surgical procedure itself. We conclude that partial gastrectomy seems to have very little impact on survival once the patient has survived the first year after operation.

The risk of gastrointestinal and other primary malignant diseases following gastric cancer.

The risk of developing a second primary cancer was studied among 34,506 gastric cancer patients identified through the Swedish Cancer Registry. A second cancer was reported in 962 patients compared to an expected number of 826 (relative risk = 1.16, 95% confidence limits = 1.09-1.24). The slightly but significantly elevated risk was largely confined to the first year after the gastric cancer diagnosis, and to patients under 70 years old at the time of diagnosis. The risk was significantly increased for cancer in the small intestine, colon, rectum, kidney, breast and prostate. A closer look at the data, however, revealed that a substantial proportion of the second cancers were diagnosed within one month after the gastric cancer diagnosis, or at autopsy. We recalculated the relative risk estimates under the assumption that only 75% of the cancers incidentally detected in connection with diagnosis/treatment of the gastric cancer would have become clinically manifest during the relatively short observation time. and that 20% of the cancers revealed at autopsy in the gastric cancer patients would have been detected if the death and autopsy rates in this group had been equal to those in the general population (matched for age and gender). Under those assumptions the risk of having a second primary cancer among gastric cancer patients was close to what would be expected. The increased risk reported in some previous studies could be the result of closer patient surveillance.

The risk of large bowel cancer after partial gastrectomy for benign ulcer disease.

The relative risk (standardized incidence ratio [SIR] for colorectal cancer after partial gastrectomy for ulcer disease was examined in a population-based cohort comprising 6459 patients operated during 1950 to 1958. Follow-up through 1983 revealed 131 cases of colorectal cancer versus 150.3 expected cases (SIR = 0.87; 95% confidence limits 0.73, 1.03). The relative risk was decreased during the first 19 years of follow-up (SIR = 0.75; 0.58, 0.96) and close to equal thereafter (SIR = 1.02; 0.79, 1.29). Sex, age at operation, type of operation, and diagnosis at operation (stomach or duodenal ulcer) did not affect the relative risk significantly. Confounding by socioeconomic status is one conceivable explanation for the decreased relative risk during the first years of follow-up, whereas the increasing risk with longer duration of follow-up might be a consequence of the surgical procedure itself.

Stomach cancer after partial gastrectomy for benign ulcer disease.

We followed for 25 to 33 years 6459 patients who had undergone partial gastrectomy for benign ulcer disease to determine the incidence of stomach cancer. The overall risk was no different from that among sex- and age-matched controls from the Swedish Cancer Registry (standardized incidence ratio = 0.96; 95 percent confidence limits, 0.78 and 1.16). However, when the patients were classified according to the duration of follow-up after operation, sex, surgical procedure, diagnosis at the time of operation, and age at operation, differences in risk were observed between the subgroups. After adjustment for potential confounding variables, the average adjusted risk increased 28 percent (adjusted standardized incidence ratio = 1.28; 95 percent confidence limits, 1.11 and 1.49) for each successive five-year interval after operation. The adjusted risk was greater among women than men (adjusted standardized incidence ratio = 1.96; 95 percent confidence limits, 1.18 and 3.24). Patients who had undergone a Billroth I anastomosis had a lower crude risk, both overall (standardized incidence ratio = 0.40; 95 percent confidence limits, 0.20 and 0.71) and after we controlled for other confounding variables (adjusted standardized incidence ratio = 0.27; 95 percent confidence limits, 0.12 and 0.62), than did those who had undergone a Billroth II procedure. The adjusted risk of stomach cancer was greater among patients operated on for gastric ulcer than among those operated on for duodenal ulcer (adjusted standardized incidence ratio = 2.21; 95 percent confidence limits, 1.45 and 3.35). Risk decreased with increased age at operation. Between successive strata of age at operation (less than 39, 40 to 49, 50 to 59, and greater than or equal to 60 years of age), the adjusted risk decreased on the average by about half (adjusted standardized incidence ratio = 0.52; 95 percent confidence limits, 0.41 and 0.66).

Cancer of the stomach after operation for benign ulcer disease.

Despite a great number of studies during almost three decades it has not been possible to satisfactorily answer the question how the risk of developing cancer of the stomach is affected by operation for ulcer disease. The answer to this question is interesting from a tumourbiological point of view and practically important when choosing treatment and follow-up routines. In principle this can be said to be a test case for clinical problems that can be solved most effectively by epidemiological research methods. In this brief survey are summarized first the state of knowledge in the field and the methodological problems that have made it hard to study the question. Then a historical cohort study is reported which has just been finished in the health care region of Uppsala. By following a sufficiently great number of individuals (fully 6,000) over a long time (25-33 years) and using multivariate methods of analysis it was possible to demonstrate a consistent and complex pattern of a changed risk of cancer of the stomach after partial gastrectomy according to Billroth I and II. Not only the choice of surgical method influences this risk but also age at operation, diagnosis, the length of the observational follow-up, and the sex of the patient.

Gastric cancer survival in Sweden. Lack of improvement in 19 years.

A total of 34,549 patients constituting 87.0% of all patients with gastric cancer diagnosed in Sweden in 1960-1978 and reported to the National Cancer Registry were included in a complete follow-up over a period of 1-20 years. The poor outcome in this disease was again established in this unselected material. Thus, the 5-year relative survival rate (with 95% confidence limits) was 12.7% (12.1-13.2%) among the men and 14.1% (13.4-14.9%) among the women, without any long-term difference between the sexes. The annual hazard rates in male and female patients were still 11.0% (8.3-13.7%) and 9.0% (7.1-10.9%), respectively, after 5 years and did not approach zero until 10 years after the diagnosis. Men older than 75 showed a slightly higher mortality during the first year, but there were seemingly no relationships of tumor-biological or clinical significance between age at diagnosis and long-term relative survival. The overall prognosis remained unchanged during the 19 years of the study, whereas the incidence was reduced by about 40% in the whole Swedish population.