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Dr. Gary Maassen, MD

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Specializes in: Internal Medicine (Adult Medicine)

5034 Griffin Road
Saint Louis, MO 63128

(314) 843-7333

Dr. Gary Maassen, MD is an internist in Saint Louis, MO specializing in internal medicine (adult medicine).

Office Locations

5034 Griffin Road
Saint Louis, MO 63128

(314) 843-7333

(314) 843-9946

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Noteworthy Medicare Patient Procedures Performed by Dr. Gary Maassen, MD in 2023

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

Top 5%

By Affordability:

parathyroid hormone test

In 2023, Dr. Gary Maassen, MD had a list price for parathyroid hormone (PTH) test that was lower than the list prices billed to Medicare by 95% of providers in related specialties within Missouri. 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 10%

By Affordability:

immunization

vaccines

In 2023, Dr. Gary Maassen, MD had a list price for immunization (preventive vaccines), and vaccines that was lower than the list prices billed to Medicare by 90% of providers in related specialties within Missouri. 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:

blood draw

blood tests

phlebotomy for lab tests

preventive care

By Affordability:

flu shot

flu vaccine

In 2012, among providers in related specialties within Missouri, Dr. Gary Maassen, MD performed more blood draw, blood tests, phlebotomy for lab tests, and preventive care procedures for Medicare patients than 75% of them and he also had a list price for flu shot, and flu vaccine 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. Gary Maassen, MD treated as an internist in Saint Louis, MO during 2012 were lab tests, blood draw, preventive care and diabetes management.

Volume of procedures performed by Dr. Gary Maassen, MD for Medicare patients.

blood draw	541
diabetes management	85
doctor visit	548
lab tests	1150
preventive care	325
thoracic (chest) imaging	14
thyroid function tests	74
vaccines	13
X-rays	14

Medicare Procedure and Patient Information

2013 Medicare Procedure Volume

The top procedures that Dr. Gary Maassen, MD treated as an internist in Saint Louis, MO during 2013 were lab tests, blood draw, preventive care and diabetes management.

Volume of procedures performed by Dr. Gary Maassen, MD for Medicare patients.

aspiration	21
blood draw	484
diabetes management	73
doctor visit	507
injections	21
lab tests	955
preventive care	261
thoracic (chest) imaging	11
thyroid function tests	48
vaccines	25
X-rays	11

2013 Medicare Patient Data

Information about Medicare patients treated by Dr. Gary Maassen, MD.

**Gender**
Male	89
Female	94

**Age**
From 65 to 74	79
From 75 to 84	64
85 and over	24
Less than 65	16

Conditions of Medicare patients treated by Dr. Gary Maassen, MD in 2013

Hypertension	73
High Cholesterol	61
Stroke	0
Ischemic Heart Disease	27
Depression	25
Chronic Kidney Disease	28
Asthma	7
Osteoperosis	8
Atrial Fibrilation	7
Heart Failure	12
Chronic Obstructive Pulmonary Disease	11
Diabetes	20
Dementia	8
Cancer	11

Medicare Procedure and Patient Information

2014 Medicare Procedure Volume

The top procedures that Dr. Gary Maassen, MD treated as an internist in Saint Louis, MO during 2014 were lab tests, blood draw, preventive care and diabetes management.

Volume of procedures performed by Dr. Gary Maassen, MD for Medicare patients.

aspiration	20
blood draw	472
diabetes management	75
doctor visit	461
injections	20
lab tests	1033
preventive care	268
thoracic (chest) imaging	14
thyroid function tests	65
vaccines	38
X-rays	14

2014 Medicare Patient Data

Information about Medicare patients treated by Dr. Gary Maassen, MD.

**Gender**
Male	87
Female	86

**Age**
From 65 to 74	75
From 75 to 84	54
85 and over	28
Less than 65	16

Conditions of Medicare patients treated by Dr. Gary Maassen, MD in 2014

Hypertension	75
High Cholesterol	56
Stroke	0
Ischemic Heart Disease	29
Depression	27
Chronic Kidney Disease	28
Asthma	0
Osteoperosis	11
Atrial Fibrilation	10
Heart Failure	16
Chronic Obstructive Pulmonary Disease	10
Diabetes	22
Dementia	10
Cancer	10

Medicare Procedure and Patient Information

2015 Medicare Procedure Volume

The top procedures that Dr. Gary Maassen, MD treated as an internist in Saint Louis, MO during 2015 were lab tests, blood draw, preventive care and diabetes management.

Volume of procedures performed by Dr. Gary Maassen, MD for Medicare patients.

blood draw	469
diabetes management	81
doctor visit	503
lab tests	1138
preventive care	274
thyroid function tests	64
vaccines	43

2015 Medicare Patient Data

Information about Medicare patients treated by Dr. Gary Maassen, MD.

**Gender**
Male	188
Female	194

**Age**
From 65 to 74	158
From 75 to 84	126
85 and over	74
Less than 65	24

Conditions of Medicare patients treated by Dr. Gary Maassen, MD in 2015

Hypertension	75
High Cholesterol	68
Stroke	0
Ischemic Heart Disease	29
Depression	24
Chronic Kidney Disease	31
Asthma	9
Osteoperosis	10
Atrial Fibrilation	15
Heart Failure	15
Chronic Obstructive Pulmonary Disease	15
Diabetes	22
Dementia	7
Cancer	9

Medicare Procedure and Patient Information

2016 Medicare Procedure Volume

The top procedures that Dr. Gary Maassen, MD treated as an internist in Saint Louis, MO during 2016 were lab tests, blood draw, preventive care and diabetes management.

Volume of procedures performed by Dr. Gary Maassen, MD for Medicare patients.

aspiration	18
blood draw	496
diabetes management	81
doctor visit	504
injections	18
lab tests	1160
preventive care	304
thyroid function tests	62
vaccines	79

2016 Medicare Patient Data

Information about Medicare patients treated by Dr. Gary Maassen, MD.

**Gender**
Male	97
Female	98

**Age**
From 65 to 74	82
From 75 to 84	61
85 and over	39
Less than 65	13

Conditions of Medicare patients treated by Dr. Gary Maassen, MD in 2016

Hypertension	75
High Cholesterol	73
Stroke	0
Ischemic Heart Disease	34
Depression	27
Chronic Kidney Disease	36
Asthma	21
Osteoperosis	13
Atrial Fibrilation	13
Heart Failure	16
Chronic Obstructive Pulmonary Disease	18
Diabetes	22
Dementia	7
Cancer	7

Medicare Procedure and Patient Information

2017 Medicare Procedure Volume

The top procedures that Dr. Gary Maassen, MD treated as an internist in Saint Louis, MO during 2017 were lab tests, blood draw, preventive care and vaccines.

Volume of procedures performed by Dr. Gary Maassen, MD for Medicare patients.

aspiration	16
blood draw	428
chronic care	78
diabetes management	76
doctor visit	505
injections	16
lab tests	824
preventive care	312
thyroid function tests	49
vaccines	94

2017 Medicare Patient Data

Information about Medicare patients treated by Dr. Gary Maassen, MD.

**Gender**
Male	97
Female	99

**Age**
From 65 to 74	88
From 75 to 84	61
85 and over	36
Less than 65	11

Conditions of Medicare patients treated by Dr. Gary Maassen, MD in 2017

Hypertension	74
High Cholesterol	67
Stroke	0
Ischemic Heart Disease	31
Depression	24
Chronic Kidney Disease	36
Asthma	6
Osteoperosis	12
Atrial Fibrilation	13
Heart Failure	18
Chronic Obstructive Pulmonary Disease	16
Diabetes	21
Dementia	7
Cancer	9

Medicare Procedure and Patient Information

2018 Medicare Procedure Volume

The top procedures that Dr. Gary Maassen, MD treated as an internist in Saint Louis, MO during 2018 were lab tests, blood draw, preventive care and chronic care.

Volume of procedures performed by Dr. Gary Maassen, MD for Medicare patients.

aspiration	15
blood draw	419
chronic care	99
diabetes management	76
doctor visit	447
injections	15
lab tests	856
preventive care	225
thyroid function tests	49
vaccines	17

2018 Medicare Patient Data

Information about Medicare patients treated by Dr. Gary Maassen, MD.

**Gender**
Male	93
Female	85

**Age**
From 65 to 74	75
From 75 to 84	58
85 and over	0
Less than 65	0

Conditions of Medicare patients treated by Dr. Gary Maassen, MD in 2018

Hypertension	75
High Cholesterol	71
Stroke	0
Ischemic Heart Disease	34
Depression	24
Chronic Kidney Disease	33
Asthma	0
Osteoperosis	12
Atrial Fibrilation	13
Heart Failure	16
Chronic Obstructive Pulmonary Disease	13
Diabetes	20
Dementia	9
Cancer	12

Medicare Procedure and Patient Information

2019 Medicare Procedure Volume

The top procedures that Dr. Gary Maassen, MD treated as an internist in Saint Louis, MO during 2019 were lab tests, blood draw, preventive care and diabetes management.

Volume of procedures performed by Dr. Gary Maassen, MD for Medicare patients.

blood draw	413
diabetes management	76
doctor visit	420
lab tests	922
preventive care	254
thyroid function tests	64
vaccines	44

2019 Medicare Patient Data

Information about Medicare patients treated by Dr. Gary Maassen, MD.

**Gender**
Male	89
Female	85

**Age**
From 65 to 74	77
From 75 to 84	53
85 and over	0
Less than 65	0

Conditions of Medicare patients treated by Dr. Gary Maassen, MD in 2019

Hypertension	75
High Cholesterol	75
Stroke	0
Ischemic Heart Disease	31
Depression	25
Chronic Kidney Disease	36
Asthma	0
Osteoperosis	9
Atrial Fibrilation	13
Heart Failure	14
Chronic Obstructive Pulmonary Disease	11
Diabetes	20
Dementia	11
Cancer	14

Medicare Procedure and Patient Information

2020 Medicare Procedure Volume

The top procedures that Dr. Gary Maassen, MD treated as an internist in Saint Louis, MO during 2020 were lab tests, blood draw, preventive care and diabetes management.

Volume of procedures performed by Dr. Gary Maassen, MD for Medicare patients.

blood draw	325
diabetes management	62
doctor visit	321
lab tests	620
preventive care	196
thyroid function tests	49
vaccines	43

2020 Medicare Patient Data

Information about Medicare patients treated by Dr. Gary Maassen, MD.

**Gender**
Male	95
Female	81

**Age**
From 65 to 74	87
From 75 to 84	49
85 and over	0
Less than 65	0

Conditions of Medicare patients treated by Dr. Gary Maassen, MD in 2020

Hypertension	75
High Cholesterol	66
Stroke	0
Ischemic Heart Disease	30
Depression	23
Chronic Kidney Disease	34
Asthma	0
Osteoperosis	9
Atrial Fibrilation	7
Heart Failure	15
Chronic Obstructive Pulmonary Disease	10
Diabetes	20
Dementia	10
Cancer	13

Medicare Procedure and Patient Information

2021 Medicare Procedure Volume

The top procedures that Dr. Gary Maassen, MD treated as an internist in Saint Louis, MO during 2021 were lab tests, blood draw, preventive care and diabetes management.

Volume of procedures performed by Dr. Gary Maassen, MD for Medicare patients.

aspiration	17
blood draw	313
diabetes management	85
doctor visit	288
injections	17
lab tests	642
preventive care	216
thyroid function tests	41
vaccines	38

2021 Medicare Patient Data

Information about Medicare patients treated by Dr. Gary Maassen, MD.

**Gender**
Male	79
Female	84

**Age**
From 65 to 74	74
From 75 to 84	52
85 and over	0
Less than 65	0

Conditions of Medicare patients treated by Dr. Gary Maassen, MD in 2021

Hypertension	75
High Cholesterol	64
Stroke	0
Ischemic Heart Disease	27
Depression	25
Chronic Kidney Disease	33
Asthma	0
Osteoperosis	8
Atrial Fibrilation	7
Heart Failure	15
Chronic Obstructive Pulmonary Disease	9
Diabetes	21
Dementia	10
Cancer	12

Medicare Procedure and Patient Information

2022 Medicare Procedure Volume

The top procedures that Dr. Gary Maassen, MD treated as an internist in Saint Louis, MO during 2022 were lab tests, blood draw, preventive care and diabetes management.

Volume of procedures performed by Dr. Gary Maassen, MD for Medicare patients.

blood draw	355
diabetes management	89
doctor visit	311
lab tests	783
preventive care	231
thyroid function tests	58
vaccines	45

2022 Medicare Patient Data

Information about Medicare patients treated by Dr. Gary Maassen, MD.

**Gender**
Male	83
Female	72

**Age**
From 65 to 74	80
From 75 to 84	44
85 and over	0
Less than 65	0

Conditions of Medicare patients treated by Dr. Gary Maassen, MD in 2022

Hypertension	75
High Cholesterol	75
Stroke	0
Ischemic Heart Disease	26
Depression	22
Chronic Kidney Disease	30
Asthma	8
Osteoperosis	0
Atrial Fibrilation	20
Heart Failure	15
Chronic Obstructive Pulmonary Disease	9
Diabetes	25
Dementia	8
Cancer	20

Medicare Procedure and Patient Information

Average Medicare Procedure Volume From 2012 - 2022

Volume of procedures performed by Dr. Gary Maassen, MD for Medicare patients.

The highest averages for the top procedures that Dr. Gary Maassen, MD treated as an internist in Saint Louis, MO were lab tests, blood draw, preventive care and chronic care.

aspiration	17
blood draw	428
chronic care	88
diabetes management	78
doctor visit	437
injections	17
lab tests	916
preventive care	260
thoracic (chest) imaging	13
thyroid function tests	56
vaccines	43
X-rays	13

Average Medicare Patient Data From 2012 - 2022

Information about Medicare patients treated by Dr. Gary Maassen, MD.

**Gender**
Male	90
Female	88

**Age**
75 to 84	56
85 and over	18
Less than 65	7
65 to 74	79

Average of Total of Conditions of Medicare patients treated by Dr. Gary Maassen, MD From 2012 - 2022

The highest averages of the most common conditions of Medicare patients that Dr. Gary Maassen, MD treated were hypertension, high cholesterol, chronic kidney disease and ischemic heart disease.

Hypertension	67
High Cholesterol	61
Stroke	0
Ischemic Heart Disease	27
Depression	22
Chronic Kidney Disease	29
Asthma	4
Osteoporosis	8
Heart Failure	13
Chronic Obstructive Pulmonary Disease	11
Diabetes	19
Atrial Fibrillation	10
Dementia	7
Cancer	10

Education & Training

He has a state license in Missouri.

Licensed In: Missouri

Ratings & Reviews

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General Payments

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

**Payments by Company**
AstraZeneca Pharmaceuticals LP	$856 FARXIGA $357	CRESTOR $148	SYMBICORT $75	BYDUREON WEEKLY $60	ONGLYZA $47	Other $169
Novo Nordisk Inc	$847 Ozempic $232	Victoza $153	Tresiba $149	Saxenda $144	RYBELSUS $81	Other $88
Pfizer Inc.	$765 ELIQUIS $452	VIAGRA $96	COLOGUARD DNA CAPTURE REAGENTS $78	PAXLOVID $30	LYRICA $24	Other $86
SANOFI-AVENTIS U.S. LLC	$639 TOUJEO $289	SOLIQUA 100/33 $203	SOLIQUA $84	LANTUS $19	PRALUENT $18	Other $25
Boehringer Ingelheim Pharmaceuticals, Inc.	$587 SPIRIVA RESPIMAT $201	Pradaxa $84	STIOLTO $79	STIOLTO RESPIMAT $40	TRADJENTA $33	Other $150
Other	$3,728 Myrbetriq $257	ELIQUIS $226	Vascepa $214	INVOKANA $204	Vesicare $199	Other $2,626