Minor Surgical Procedures

The Clinformatics™ Data Mart captures administrative health claims across the United States for members of a large national managed care company affiliated with OptumInsight (Eden Prairie, MN). We examined claims from January 1, 2012 to June 30, 2015 among adults ages 18 to 64 to capture surgical procedures performed between 2013 and 2014 to account for the 12-month preoperative and 6-month postoperative study period. We included only individuals with continuous medical and prescription drug coverage to evaluate the complete health care experience. We excluded patients ages 18 and younger, as well as patients older than 64 years due to incomplete capture of Medicare Part D prescriptions claims data. The study was deemed exempt from review by the University of Michigan Institutional Review Board.
We selected 13 common elective surgical procedures, and categorized these into minor and major groups based on prior literature. Minor surgical procedures included varicose vein removal, laparoscopic cholecystectomy, laparoscopic appendectomy, hemorrhoidectomy, thyroidectomy, transurethral prostate surgeries, and parathyroidectomy. Major surgical procedures included ventral incisional hernia repair, colectomy, reflux surgery, bariatric surgery, and hysterectomy. We identified patients undergoing surgery using Current Procedural Terminology (CPT) or International Statistical Classification of Diseases and Related Health Problems (ICD9_ procedure codes (Supplemental Table 1).
We sought to determine new persistent opioid use after surgery, and included only patients who filled an opioid prescription fill either in the month prior to surgery or within two weeks after discharge. Comparable to previous studies of opioid naïve surgical populations,^{7 (link),8} patients who had filled one or more prescriptions for opioids 12 months to 31 days prior to their surgical procedure were excluded from the analysis (Figure 1). To account for prescriptions provided preoperatively for postoperative pain control, patients filling opioids in the 30 days prior to surgery were included, and prescriptions filled in this time was included as a covariate in the analyses. Lastly, we excluded patients who underwent additional surgical procedures during the study period using subsequent procedural codes for anesthesia in the 6-month postoperative period.
As a comparison cohort of patients who did not undergo surgery, we identified a random 10% sample patients ages 18 to 64 years of age who did not undergo surgery in the study period We included only patients in the nonoperative group who did not fill an opioid prescription during a 12 month period and did not have any codes for surgical procedures or anesthesia during this period. These patients were then given a random date of surgery. No patients had an opioid fill in the year prior to their fictitious surgery date nor did they have any anesthesia codes in the 6 months following their fictitious surgery date.

CONVERGE collected cases of recurrent major depression from 58 provincial mental health centres and psychiatric departments of general medical hospitals in 45 cities and 23 provinces of China. Controls were recruited from patients undergoing minor surgical procedures at general hospitals (37%) or from local community centres (63%). A sample size of 6,000 cases and 6,000 controls was chosen on the basis of evidence available when the study was designed (in 2007) of the likely existence of genetic loci with odds ratio of 1.2 and above. All subjects were Han Chinese women with four Han Chinese grandparents. Cases were excluded if they had a pre-existing history of bipolar disorder, psychosis or mental retardation. Cases were aged between 30 and 60 and had two or more episodes of MDD meeting DSM-IV criteria²⁰ with the first episode occurring between 14 and 50 years of age, and had not abused drugs or alcohol before their first depressive episode. All subjects were interviewed using a computerized assessment system. Interviewers were postgraduate medical students, junior psychiatrists or senior nurses, trained by the CONVERGE team for a minimum of one week. The diagnosis of MDD was established with the Composite International Diagnostic Interview (CIDI) (WHO lifetime version 2.1; Chinese version), which utilized DSM-IV criteria. The interview was originally translated into Mandarin by a team of psychiatrists in Shanghai Mental Health Centre, with the translation reviewed and modified by members of the CONVERGE team.
The replication sample was obtained from five hospitals in the north of China. Patients were diagnosed as having MDD by at least two consultant psychiatrists by DSM-IV criteria. Samples were of both sexes, and all four grandparents were Han Chinese. Cases were aged between 30 and 60, and had two or more episodes of MDD meeting DSM-IV criteria. Exclusion criteria were pregnancy, severe medical conditions, abnormal laboratory baseline values, unstable psychiatric features (e.g., suicidal), a history of alcoholism or drug abuse, epilepsy, brain trauma with loss of consciousness, neurological illness, or a concomitant Axis I psychiatric disorder. Control subjects were recruited from local communities and provided information about medical and family histories. Exclusion criteria were a history of major psychiatric or neurological disorders, psychiatric treatment or drug abuse, or family history of severe forms of psychiatric disorders.
The study protocol was approved centrally by the Ethical Review Board of Oxford University (Oxford Tropical Research Ethics Committee) and the ethics committees of all participating hospitals in China. All interviewers were mental health professionals who are well able to judge decisional capacity. The study posed minimal risk (an interview and saliva sample). All participants provided their written informed consent.