America’s Gut Check

The following methodology is associated with a study that we conducted on select chronic gastrointestinal conditions. Read the full report here.

Where are these numbers coming from?

We looked at every patient in our database between 0 and 83 years of age who was diagnosed with at least one of the following gut-related conditions between January 2014 and December 2015.*

Condition Total Patients Male Patients Female Patients
Acid reflux (GERD) 2,564,700 1,038,300 1,526,400
Gallstones 1,050,800 335,300 715,500
Ulcerative colitis 501,100 231,400 269,700
Irritable bowel syndrome (IBS) 344,300 88,000 256,200
Colon cancer 326,000 167,400 158,700
Crohn’s disease 266,900 120,300 146,600
Celiac disease 52,900 15,800 37,100
Total distinct patients 4,719,900 1,837,700 2,882,200

* All data is rounded to the nearest 100 for patient privacy purposes.

We also looked at every patient in our database that had a colonoscopy between January 2014 and December 2015.*

Procedure Total Patients Male Patients Female Patients
Colonoscopy 5,964,800 2,762,400 3,202,400

* All data is rounded to the nearest 100 for patient privacy purposes.

How did you determine the relationship between gut-related conditions and other symptoms/conditions?

To find out what symptoms and conditions are commonly associated with our selection of gut-related diseases, we looked for specific patient/doctor interactions where the doctor indicated that more than one condition was present at the time of the interaction.

For example, a doctor could indicate that a patient has both irritable bowel syndrome (IBS) and lactose intolerance in the same visit. This practice is known as “documenting comorbid conditions” and is a common practice in medical claims.

Once we identified patients who were diagnosed with at least one of the selected gut-related conditions, we collected and analyzed their comorbid conditions for each visit. We measured the proportion of these comorbid conditions among our population of patients with the selected gut-related conditions, and compared those numbers to the proportion found in patients who don’t have the selected gut-related conditions. We then applied a technique that ranks conditions based on how uniquely associated they are with patients who have the selected gut-related conditions.

Want to know more about this technique? Great! Let’s keep going.

Consider the example of finding unique conditions associated with patients who are diagnosed with IBS. For this analysis, we split our population of patients into two groups: patients diagnosed with IBS and patients who weren’t diagnosed with IBS.

First, we identified all of the comorbid conditions that patients with IBS were diagnosed with to calculate the proportion of visits where these conditions were found. For example, to determine the proportion of patients diagnosed with IBS and lactose intolerance, we tallied all of the patients who were diagnosed with both diseases, then divided that number by the total number of patients diagnosed with IBS in our patient group. Next, we identified all the distinct comorbid conditions for patients that weren’t diagnosed with IBS and calculated the proportion of visits where these conditions were found. This allowed us to compare the relative frequency of conditions between our two groups of patients.

To compare the relative frequency of conditions associated with patients diagnosed with IBS versus patients who weren’t diagnosed with IBS, we formed something called a relative frequency ratio for each condition. For the example of IBS patients with lactose intolerance, we divided the estimated proportion of patients with IBS and lactose intolerance by the estimated proportion of patients who have lactose intolerance (but not IBS). A ratio greater than 1 suggests that lactose intolerance occurs at a higher relative rate among patients with IBS versus patients who don’t have IBS. In fact, our data shows that patients with IBS are 10 times more frequently associated with lactose intolerance versus patients who don’t have IBS!

To avoid showing a list of comorbid conditions that are exceedingly rare, we excluded comorbid conditions that belonged to less than 0.1% of patients with a specific gut-related condition. For example, if we had 1 million patients diagnosed with IBS in our dataset, we excluded comorbid conditions that affect less than 1,000 of these IBS patients. That’s all there is to it! If you made it this far, tweet @AminoHealth “Hot biopsy forceps!” and we’ll send you a sticker as a reward for your perseverance.

How did you determine the outcomes of colonoscopies?

There are different types of colonoscopies, and each is represented by a unique code in Amino’s database. We first identified every type of colonoscopy found in our database, and then manually grouped them into three categories:

  • Colorectal cancer screening colonoscopies that resulted in a biopsy or removal of a polyp, lesion, or tumor (labeled as “removal”)
  • Colorectal cancer screening colonoscopies that didn’t result in a biopsy or removal of a polyp, lesion, or tumor (labeled as “screening”)
  • Colonoscopies not associated with colorectal cancer screening (labeled as “other”)

You can find the complete list of codes used for our analyses (and how we categorized them) below.

A small proportion of patients (2.3% of our patient group) underwent more than one colonoscopy between January 2014 and December 2015. For these patients, we focused on the first colonoscopy conducted to determine the category of outcome.

Code Source Description Category
45378 CPT Diagnostic flexible colonoscopy proximal to splenic flexure screening
G0121 HCPCS Colorectal cancer screening; colonoscopy on individual not meeting criteria for high risk screening
G0105 HCPCS Colorectal cancer screening; colonoscopy on individual at high risk screening
44388 CPT Diagnostic colonoscopy through stoma screening
44389 CPT Colonoscopy through stoma with biopsy screening
G0120 HCPCS Colorectal cancer screening; alternative to g0105 screening colonoscopy barium enema. screening
45380 CPT Flexible colonoscopy proximal to splenic flexure with biopsy removal
45385 CPT Flexible colonoscopy proximal to splenic flexure with removal of lesion using snare removal
45384 CPT Flexible colonoscopy proximal to splenic flexure with removal of lesion using hot biopsy forceps removal
45383 CPT Flexible colonoscopy proximal to splenic flexure with ablation of polyp removal
44394 CPT Colonoscopy through stoma with removal of lesion using snare removal
44392 CPT Colonoscopy through stoma with removal of lesion using bipolar cautery removal
44393 CPT Colonoscopy through stoma with ablation of lesion removal
45381 CPT Flexible colonoscopy proximal to splenic flexure with directed submucosal injection other
4523 ICD9v3 Colonoscopy other
4525 ICD9v3 Closed (endoscopic) biopsy of large intestine other
45382 CPT Flexible colonoscopy proximal to splenic flexure with control of bleeding other
45386 CPT Flexible colonoscopy proximal to splenic flexure with dilation of stricture using balloon other
45379 CPT Flexible colonoscopy proximal to splenic flexure with removal of foreign body other
45391 CPT Flexible colonoscopy proximal to splenic flexure with endoscopic ultrasound examination other
45355 CPT Flexible colonoscopy by transabdominal approach via colotomy other
45387 CPT Flexible colonoscopy proximal to splenic flexure with predilation and transendoscopic stent placement other
45392 CPT Flexible colonoscopy proximal to splenic flexure with transendoscopic intramural fine needle aspiration using ultrasound guidance other
44391 CPT Colonoscopy through stoma with control of bleeding other
44390 CPT Colonoscopy through stoma with removal of foreign body other
44397 CPT Colonoscopy through stoma with transendoscopic stent placement and predilation other

For more information about any of our methodologies, emailinsights@amino.com.

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