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Dr. William C. Bayer, MD

Accepting New Patients

(William C. Bayer, MD)

(107 Ratings)

Specializes in: Physician and Endocrinology Diabetes & Metabolism

Loyola University Stritch School of Medicine (1986)

233 S Gary Avenue
Bloomingdale, IL 60108

(630) 208-6775

Dr. William C. Bayer, MD is a physician provider in Bloomingdale, IL specializing in physician and endocrinology diabetes & metabolism. He graduated from Loyola University Stritch School of Medicine in 1986 and has 40 years of experience. Dr. William C. Bayer, MD is affiliated with Northwestern Medicine and Northwestern Medicine Regional Medical Group.

Office Locations

233 S Gary Avenue
Bloomingdale, IL 60108

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Noteworthy Medicare Patient Procedures Performed by Dr. William C. Bayer, MD in 2024

Click on any procedure below to see further details on volume and pricing among Medicare patients.

Top 10%

By Affordability:

A1C test

glycated protein test

In 2024, Dr. William C. Bayer, MD had a list price for A1C test, and glycated protein test that was lower than the list prices billed to Medicare by 90% of providers in related specialties within Illinois. Actual amounts paid by patients can vary widely depending on a number of factors, including insurance coverage. A lower list price, however, might mean lower fees when paying without insurance.

Top 25%

By Volume:

A1C test

By Affordability:

inpatient hospital care

preventive care

screening test

In 2012, among providers in related specialties within Illinois, Dr. William C. Bayer, MD performed more A1C test procedures for Medicare patients than 75% of them and he also had a list price for diabetes management, diabetes screening, hospital care, inpatient care, inpatient hospital care (for patient admitted to hospital), preventive care, and screening test that was lower than the list prices billed to Medicare by 75% of them. Actual amounts paid by patients can vary widely depending on a number of factors, including insurance coverage. A lower list price, however, might mean lower fees when paying without insurance.

Medicare Procedure and Patient Information

2012 Medicare Procedure Volume

The top procedures that Dr. William C. Bayer, MD treated as a physician provider in Bloomingdale, IL during 2012 were hospital care, inpatient care, ultrasound (sonogram) and neck imaging.

Volume of procedures performed by Dr. William C. Bayer, MD for Medicare patients.

doctor visit	807
hospital care	142
inpatient care	142
lab tests	19
neck imaging	91
preventive care	49
ultrasound (sonogram)	91
vaccines	30

Medicare Procedure and Patient Information

2013 Medicare Procedure Volume

The top procedures that Dr. William C. Bayer, MD treated as a physician provider in Bloomingdale, IL during 2013 were hospital care, inpatient care, ultrasound (sonogram) and neck imaging.

Volume of procedures performed by Dr. William C. Bayer, MD for Medicare patients.

doctor visit	812
hospital care	162
inpatient care	162
lab tests	22
neck imaging	119
preventive care	48
ultrasound (sonogram)	119
vaccines	26

2013 Medicare Patient Data

Information about Medicare patients treated by Dr. William C. Bayer, MD.

**Gender**
Male	190
Female	404

**Ethnicity**
Non-Hispanic White	535
Black	0
Hispanic	24
Asian	16
Other	0
Native American	0

**Age**
From 65 to 74	272
From 75 to 84	192
85 and over	78
Less than 65	52

Conditions of Medicare patients treated by Dr. William C. Bayer, MD in 2013

Hypertension	72
High Cholesterol	67
Stroke	4
Ischemic Heart Disease	29
Depression	17
Chronic Kidney Disease	21
Asthma	8
Osteoperosis	15
Atrial Fibrilation	13
Heart Failure	16
Chronic Obstructive Pulmonary Disease	12
Diabetes	48
Dementia	9
Cancer	11

Medicare Procedure and Patient Information

2014 Medicare Procedure Volume

The top procedures that Dr. William C. Bayer, MD treated as a physician provider in Bloomingdale, IL during 2014 were hospital care, inpatient care, ultrasound (sonogram) and neck imaging.

Volume of procedures performed by Dr. William C. Bayer, MD for Medicare patients.

diabetes management	21
doctor visit	743
hospital care	105
inpatient care	105
lab tests	21
neck imaging	40
preventive care	34
ultrasound (sonogram)	40
vaccines	13

2014 Medicare Patient Data

Information about Medicare patients treated by Dr. William C. Bayer, MD.

**Gender**
Male	173
Female	369

**Ethnicity**
Non-Hispanic White	480
Black	13
Hispanic	24
Asian	11
Other	14
Native American	0

**Age**
From 65 to 74	261
From 75 to 84	164
85 and over	69
Less than 65	48

Conditions of Medicare patients treated by Dr. William C. Bayer, MD in 2014

Hypertension	72
High Cholesterol	69
Stroke	5
Ischemic Heart Disease	28
Depression	19
Chronic Kidney Disease	19
Asthma	7
Osteoperosis	12
Atrial Fibrilation	12
Heart Failure	13
Chronic Obstructive Pulmonary Disease	11
Diabetes	48
Dementia	9
Cancer	10

Medicare Procedure and Patient Information

2015 Medicare Procedure Volume

The top procedures that Dr. William C. Bayer, MD treated as a physician provider in Bloomingdale, IL during 2015 were lab tests, preventive care, diabetes management and hospital care.

Volume of procedures performed by Dr. William C. Bayer, MD for Medicare patients.

diabetes management	136
doctor visit	733
hospital care	129
inpatient care	129
lab tests	136
preventive care	136

2015 Medicare Patient Data

Information about Medicare patients treated by Dr. William C. Bayer, MD.

**Gender**
Male	330
Female	690

**Ethnicity**
Non-Hispanic White	894
Black	22
Hispanic	36
Asian	38
Other	30
Native American	0

**Age**
From 65 to 74	506
From 75 to 84	302
85 and over	88
Less than 65	124

Conditions of Medicare patients treated by Dr. William C. Bayer, MD in 2015

Hypertension	71
High Cholesterol	65
Stroke	3
Ischemic Heart Disease	25
Depression	20
Chronic Kidney Disease	33
Asthma	11
Osteoperosis	13
Atrial Fibrilation	13
Heart Failure	14
Chronic Obstructive Pulmonary Disease	14
Diabetes	51
Dementia	7
Cancer	10

Medicare Procedure and Patient Information

2016 Medicare Procedure Volume

The top procedures that Dr. William C. Bayer, MD treated as a physician provider in Bloomingdale, IL during 2016 were preventive care, lab tests, diabetes management and hospital care.

Volume of procedures performed by Dr. William C. Bayer, MD for Medicare patients.

diabetes management	164
doctor visit	760
hospital care	137
inpatient care	137
lab tests	164
preventive care	177
vaccines	13

2016 Medicare Patient Data

Information about Medicare patients treated by Dr. William C. Bayer, MD.

**Gender**
Male	175
Female	378

**Ethnicity**
Non-Hispanic White	496
Black	13
Hispanic	20
Asian	13
Other	11
Native American	0

**Age**
From 65 to 74	287
From 75 to 84	158
85 and over	51
Less than 65	57

Conditions of Medicare patients treated by Dr. William C. Bayer, MD in 2016

Hypertension	70
High Cholesterol	67
Stroke	4
Ischemic Heart Disease	25
Depression	18
Chronic Kidney Disease	48
Asthma	13
Osteoperosis	13
Atrial Fibrilation	12
Heart Failure	13
Chronic Obstructive Pulmonary Disease	10
Diabetes	50
Dementia	7
Cancer	11

Medicare Procedure and Patient Information

2017 Medicare Procedure Volume

The top procedures that Dr. William C. Bayer, MD treated as a physician provider in Bloomingdale, IL during 2017 were lab tests, preventive care, diabetes management and hospital care.

Volume of procedures performed by Dr. William C. Bayer, MD for Medicare patients.

diabetes management	177
doctor visit	782
hospital care	122
inpatient care	122
lab tests	177
preventive care	177

2017 Medicare Patient Data

Information about Medicare patients treated by Dr. William C. Bayer, MD.

**Gender**
Male	190
Female	374

**Ethnicity**
Non-Hispanic White	504
Black	11
Hispanic	19
Asian	18
Other	12
Native American	0

**Age**
From 65 to 74	289
From 75 to 84	165
85 and over	53
Less than 65	57

Conditions of Medicare patients treated by Dr. William C. Bayer, MD in 2017

Hypertension	72
High Cholesterol	66
Stroke	5
Ischemic Heart Disease	29
Depression	25
Chronic Kidney Disease	46
Asthma	9
Osteoperosis	14
Atrial Fibrilation	12
Heart Failure	17
Chronic Obstructive Pulmonary Disease	14
Diabetes	50
Dementia	7
Cancer	13

Medicare Procedure and Patient Information

2018 Medicare Procedure Volume

The top procedures that Dr. William C. Bayer, MD treated as a physician provider in Bloomingdale, IL during 2018 were lab tests, preventive care, diabetes management and hospital care.

Volume of procedures performed by Dr. William C. Bayer, MD for Medicare patients.

diabetes management	162
doctor visit	765
hospital care	101
inpatient care	101
lab tests	162
preventive care	162

2018 Medicare Patient Data

Information about Medicare patients treated by Dr. William C. Bayer, MD.

**Gender**
Male	201
Female	387

**Ethnicity**
Non-Hispanic White	514
Black	0
Hispanic	26
Asian	21
Other	0
Native American	0

**Age**
From 65 to 74	299
From 75 to 84	174
85 and over	54
Less than 65	61

Conditions of Medicare patients treated by Dr. William C. Bayer, MD in 2018

Hypertension	71
High Cholesterol	75
Stroke	4
Ischemic Heart Disease	27
Depression	24
Chronic Kidney Disease	46
Asthma	10
Osteoperosis	18
Atrial Fibrilation	11
Heart Failure	16
Chronic Obstructive Pulmonary Disease	11
Diabetes	48
Dementia	7
Cancer	13

Medicare Procedure and Patient Information

2019 Medicare Procedure Volume

The top procedures that Dr. William C. Bayer, MD treated as a physician provider in Bloomingdale, IL during 2019 were lab tests, preventive care, diabetes management and hospital care.

Volume of procedures performed by Dr. William C. Bayer, MD for Medicare patients.

diabetes management	182
doctor visit	834
hospital care	50
inpatient care	50
lab tests	182
preventive care	182

2019 Medicare Patient Data

Information about Medicare patients treated by Dr. William C. Bayer, MD.

**Gender**
Male	188
Female	391

**Ethnicity**
Non-Hispanic White	515
Black	12
Hispanic	19
Asian	18
Other	15
Native American	0

**Age**
From 65 to 74	283
From 75 to 84	193
85 and over	59
Less than 65	44

Conditions of Medicare patients treated by Dr. William C. Bayer, MD in 2019

Hypertension	72
High Cholesterol	75
Stroke	3
Ischemic Heart Disease	27
Depression	24
Chronic Kidney Disease	44
Asthma	8
Osteoperosis	20
Atrial Fibrilation	13
Heart Failure	15
Chronic Obstructive Pulmonary Disease	10
Diabetes	44
Dementia	7
Cancer	12

Medicare Procedure and Patient Information

2020 Medicare Procedure Volume

The top procedures that Dr. William C. Bayer, MD treated as a physician provider in Bloomingdale, IL during 2020 were lab tests, preventive care, diabetes management and hospital care.

Volume of procedures performed by Dr. William C. Bayer, MD for Medicare patients.

diabetes management	114
doctor visit	648
hospital care	57
inpatient care	57
lab tests	114
preventive care	114

2020 Medicare Patient Data

Information about Medicare patients treated by Dr. William C. Bayer, MD.

**Gender**
Male	208
Female	384

**Ethnicity**
Non-Hispanic White	519
Black	13
Hispanic	24
Asian	20
Other	16
Native American	0

**Age**
From 65 to 74	287
From 75 to 84	196
85 and over	61
Less than 65	48

Conditions of Medicare patients treated by Dr. William C. Bayer, MD in 2020

Hypertension	72
High Cholesterol	75
Stroke	4
Ischemic Heart Disease	27
Depression	23
Chronic Kidney Disease	48
Asthma	7
Osteoperosis	21
Atrial Fibrilation	10
Heart Failure	17
Chronic Obstructive Pulmonary Disease	9
Diabetes	47
Dementia	9
Cancer	14

Medicare Procedure and Patient Information

2021 Medicare Procedure Volume

The top procedures that Dr. William C. Bayer, MD treated as a physician provider in Bloomingdale, IL during 2021 were lab tests, preventive care, diabetes management and hospital care.

Volume of procedures performed by Dr. William C. Bayer, MD for Medicare patients.

blood draw	40
diabetes management	161
doctor visit	715
hospital care	74
inpatient care	74
lab tests	161
preventive care	161

2021 Medicare Patient Data

Information about Medicare patients treated by Dr. William C. Bayer, MD.

**Gender**
Male	196
Female	372

**Ethnicity**
Non-Hispanic White	510
Black	11
Hispanic	17
Asian	18
Other	12
Native American	0

**Age**
From 65 to 74	259
From 75 to 84	202
85 and over	58
Less than 65	49

Conditions of Medicare patients treated by Dr. William C. Bayer, MD in 2021

Hypertension	71
High Cholesterol	75
Stroke	5
Ischemic Heart Disease	27
Depression	25
Chronic Kidney Disease	50
Asthma	9
Osteoperosis	23
Atrial Fibrilation	12
Heart Failure	20
Chronic Obstructive Pulmonary Disease	11
Diabetes	49
Dementia	9
Cancer	13

Medicare Procedure and Patient Information

2022 Medicare Procedure Volume

The top procedures that Dr. William C. Bayer, MD treated as a physician provider in Bloomingdale, IL during 2022 were blood draw, lab tests, preventive care and diabetes management.

Volume of procedures performed by Dr. William C. Bayer, MD for Medicare patients.

blood draw	173
diabetes management	168
doctor visit	787
hospital care	62
inpatient care	62
lab tests	168
preventive care	168

2022 Medicare Patient Data

Information about Medicare patients treated by Dr. William C. Bayer, MD.

**Gender**
Male	225
Female	405

**Ethnicity**
Non-Hispanic White	542
Black	14
Hispanic	31
Asian	17
Other	26
Native American	0

**Age**
From 65 to 74	307
From 75 to 84	225
85 and over	57
Less than 65	41

Conditions of Medicare patients treated by Dr. William C. Bayer, MD in 2022

Hypertension	73
High Cholesterol	75
Stroke	6
Ischemic Heart Disease	25
Depression	22
Chronic Kidney Disease	32
Asthma	9
Osteoperosis	27
Atrial Fibrilation	16
Heart Failure	17
Chronic Obstructive Pulmonary Disease	11
Diabetes	48
Dementia	7
Cancer	17

Medicare Procedure and Patient Information

2023 Medicare Procedure Volume

The top procedures that Dr. William C. Bayer, MD treated as a physician provider in Bloomingdale, IL during 2023 were lab tests, preventive care, diabetes management and blood draw.

Volume of procedures performed by Dr. William C. Bayer, MD for Medicare patients.

blood draw	146
diabetes management	147
doctor visit	718
hospital care	59
inpatient care	59
lab tests	147
preventive care	147

2023 Medicare Patient Data

Information about Medicare patients treated by Dr. William C. Bayer, MD.

**Gender**
Male	207
Female	387

**Ethnicity**
Non-Hispanic White	505
Black	14
Hispanic	26
Asian	20
Other	29
Native American	0

**Age**
From 65 to 74	298
From 75 to 84	205
85 and over	54
Less than 65	37

Conditions of Medicare patients treated by Dr. William C. Bayer, MD in 2023

Hypertension	75
High Cholesterol	75
Stroke	6
Ischemic Heart Disease	24
Depression	22
Chronic Kidney Disease	29
Asthma	10
Osteoperosis	30
Atrial Fibrilation	15
Heart Failure	17
Chronic Obstructive Pulmonary Disease	11
Diabetes	48
Dementia	5
Cancer	17

Medicare Procedure and Patient Information

2024 Medicare Procedure Volume

The top procedures that Dr. William C. Bayer, MD treated as a physician provider in Bloomingdale, IL during 2024 were lab tests, preventive care, diabetes management and hospital care.

Volume of procedures performed by Dr. William C. Bayer, MD for Medicare patients.

blood draw	56
diabetes management	148
doctor visit	667
hospital care	70
inpatient care	70
lab tests	148
preventive care	148

2024 Medicare Patient Data

Information about Medicare patients treated by Dr. William C. Bayer, MD.

**Gender**
Male	205
Female	370

**Ethnicity**
Non-Hispanic White	501
Black	13
Hispanic	18
Asian	21
Other	22
Native American	0

**Age**
From 65 to 74	264
From 75 to 84	212
85 and over	65
Less than 65	34

Conditions of Medicare patients treated by Dr. William C. Bayer, MD in 2024

Hypertension	74
High Cholesterol	75
Stroke	6
Ischemic Heart Disease	26
Depression	23
Chronic Kidney Disease	32
Asthma	10
Osteoperosis	32
Atrial Fibrilation	15
Heart Failure	18
Chronic Obstructive Pulmonary Disease	11
Diabetes	48
Dementia	6
Cancer	16

Medicare Procedure and Patient Information

Average Medicare Procedure Volume From 2012 - 2024

Volume of procedures performed by Dr. William C. Bayer, MD for Medicare patients.

The highest averages for the top procedures that Dr. William C. Bayer, MD treated as a physician provider in Bloomingdale, IL were diabetes management, preventive care, lab tests and blood draw.

blood draw	103
diabetes management	143
doctor visit	751
hospital care	97
inpatient care	97
lab tests	124
neck imaging	83
preventive care	131
ultrasound (sonogram)	83
vaccines	20

Average Medicare Patient Data From 2012 - 2024

Information about Medicare patients treated by Dr. William C. Bayer, MD.

**Gender**
Male	191
Female	377

**Ethnicity**
Black / African American	10
Asian / Pacific Islander	17
Non-Hispanic White	501
Hispanic	21
Native American / Alaskan Native	0
Other	14

**Age**
75 to 84	183
85 and over	57
Less than 65	50
65 to 74	277

Average of Total of Conditions of Medicare patients treated by Dr. William C. Bayer, MD From 2012 - 2024

The highest averages of the most common conditions of Medicare patients that Dr. William C. Bayer, MD treated were high cholesterol, hypertension, diabetes and chronic kidney disease.

Hypertension	66
High Cholesterol	66
Stroke	4
Ischemic Heart Disease	24
Depression	20
Chronic Kidney Disease	34
Asthma	8
Osteoporosis	18
Heart Failure	14
Chronic Obstructive Pulmonary Disease	10
Diabetes	44
Atrial Fibrillation	11
Cancer	12
Dementia	6

Education & Training

Dr. William C. Bayer, MD graduated from Loyola University Stritch School of Medicine in 1986. He completed residency at Loyola University Medical Center. He is certified by the American Board of Internal Medicine - Internal Medicine (Certified) and has a state license in Illinois.

Medical School: Loyola University Stritch School of Medicine (1986)

Residency: Loyola University Medical Center (1989)

Board Certification: American Board of Internal Medicine - Internal Medicine (Certified)

Licensed In: Illinois

Affiliations & Hospitals

Dr. William C. Bayer, MD is associated with these hospitals and organizations:

Northwestern Medicine

Northwestern Medicine Regional Medical Group

Ratings & Reviews

Dr. William C. Bayer, MD has an exceptional overall rating with an average of 4.87 out of 5 stars based on 107 ratings. We collect ratings and reviews of Dr. William C. Bayer, MD from all over the web to help you find the right in Bloomingdale, IL.

4.87

Overall Rating

(107 Ratings)

Leave a Review

General Payments

These charts describe general payments received by Dr. William C. Bayer, MD. Doctors may receive payments for a number of reasons, including meal compensation, travel compensation, and consulting.

**Payments by Company**
Novo Nordisk Inc	$117,417 Victoza $41,577	RYBELSUS $23,869	Tresiba $17,141	Ozempic $16,898	Xultophy 100/3.6 $7,939	Other $9,993
AbbVie, Inc.	$55,178 Synthroid $31,723	Androgel $16,543	Lupron $1,356	Creon $10	$5,546
Boehringer Ingelheim Pharmaceuticals, Inc.	$50,404 JARDIANCE $31,573	GLYXAMBI $11,410	TRADJENTA $4,961	JENTADUETO $179	COMBIVENT RESPIMAT $73	Other $2,208
SANOFI-AVENTIS U.S. LLC	$34,978 TOUJEO $25,490	LANTUS $4,906	APIDRA $1,855	SOLIQUA $270	AFREZZA $84	Other $2,374
Lilly USA, LLC	$23,483 JARDIANCE $18,072	GLYXAMBI $2,313	TRADJENTA $1,929	MOUNJARO $504	TRULICITY $211	Other $454
Other	$34,994 INVOKANA $14,256	BYDUREON $7,579	FARXIGA $3,296	Synthroid $3,004	ATELVIA $1,009	Other $5,850

**Types of Payments**
Compensation for services other than consulting, including serving as faculty or as a speaker at a venue other than a continuing education program	$263,361
Food and Beverage	$27,959
Travel and Lodging	$13,015
Consulting Fee	$11,852
Education	$268

Ownership and Interest Payments

This table describes ownership payments received by Dr. William C. Bayer, MD.

CCPA Purchasing Partners, L.P.	2016	$15.78	Physician Covered Recipient	Limited Partnership Interest
CCPA Purchasing Partners, L.P.	2014	$15.78	Physician Covered Recipient	Limited Partnership Interest
CCPA Purchasing Partners, L.P.	2015	$15.78	Physician Covered Recipient	Limited Partnership Interest

Biography

Dr. William Bayer is a physician who specializes in general practice and endocrinology. He obtained his medical school training at Loyola University Chicago, Stritch School of Medicine and performed his residency at a hospital affiliated with Loyola University. He has a 5.0 out of 5 star average patient rating. Dr. Bayer is affiliated with Northwestern Medicine Central DuPage Hospital and Northwestern Medicine Regional Medical Group. According to Yext, new patients are welcome to contact Dr. Bayer's office in Bloomingdale, IL.