The impact of non-medical switching among ambulatory patients: an updated systematic literature review

Figures & data

Table 1. MEDLINE search strategy.

‘medication conversion’ OR ‘drug conversion’ OR ‘non-medical switch$’ OR ‘nonmedical switch$’ OR ‘non-consented switch$’ OR ‘therapeutic switch$’ OR ‘therapeutic interchange’ OR ‘therapeutic substitution’ OR ‘drug substitution’ OR ‘nonmedical switcher$’ OR ‘generic switch$’ OR ‘switcher$’ OR ‘non-medical reason’) AND (‘Adherence’ OR ‘compliance’ OR ‘persistence’ OR ‘medication discontinuation’ OR ‘drug utilization’ OR ‘quality of life’ OR ‘patient satisfaction’ OR ‘drug cost$’ OR ‘medication cost$’ OR ‘drug spending’ OR ‘medication spending’ OR ‘drug acquisition cost$’ OR ‘medication acquisition cost$’ OR ‘healthcare cost$’ OR ‘health care cost$’ OR ‘cost saving$’ OR ‘medical resource$’ OR ‘healthcare services’ OR ‘health care services’ OR ‘resource utilization’ OR ‘resource use’ OR ‘emergency room visit$’ OR ‘emergency department visit$’ OR ‘ER visit$’ OR ‘ED visit$’ OR ‘economic consequence$’ OR ‘clinical impact’ OR ‘disease activity’ OR ‘effectiveness’ OR ‘side effect$’ OR ‘adverse effect$’ OR ‘outcome$’ OR ‘total cost$’ OR ‘pharmacy cost$’)

Table 2. Characteristics of included studies.

Reference	Drug(s) Switched; Disease(s)	Data Source; Comparison Type	Funding Source	Follow-up Period	Stable/well-controlled disease	Outcome Type	Outcome	Direction of Association
Blonde ^[11] N = 1,336	Canagliflozin to different anti-glycemic agent; DM	IQVIA RWD and longitudinal prescription database; matched	Janssen Research and Development	4 months	No	Clinical	Unique anti-glycemic products used	Negative
							Anti-hypertensive medication use	Negative
							Dyslipidemia medication use	Negative
						Economic	Total diabetes-related medical costs	Negative
							Diabetes-related hospitalization costs	Neutral
							Diabetes-related ED visit costs	Neutral
							Diabetes-related outpatient visit costs	Neutral
							Diabetes-related laboratory and pathology costs	Neutral
							Diabetes-related costs for other services	Neutral
							Non-diabetes related outpatient pharmacy costs	Positive
						Resource utilization	Diabetes-related pharmacy fills	Negative
						Medication Taking Behavior	Discontinuation or switch	Negative
Flores ^[12] N = 379	Anti-glycemic agent to different anti-glycemic agent; DM	Internet-based patient survey; Pre/post	Janssen Scientific Affairs	NR	No	Clinical	Treatment satisfaction	Negative
Gibofsky ^[8] N = 4,962	Anti-TNF to different anti-TNF; RA, PS, PsA, AS, CD, UC	Humedica EHR data; Matched	Abbvie	12 months	Yes	Clinical	Any physician documented adverse clinical consequence	Negative
							Side effect	Negative
							Diminished efficacy	Negative
							Subsequent medication change	Negative
							Subsequent medication changes related to adverse consequence	Negative
						Resource Utilization	Inpatient visit	Neutral
							ER visit	Neutral
							Ambulatory visit	Negative
Naville-Cook ^[13] N = 1,520	Rosuvastatin to atorvastatin; HLD	VA; Pre/post	None	12 months	No	Clinical	LDL	Neutral
							ALT	Neutral
							AST	Neutral
							CPK	Neutral
							Alkaline phosphatase	Negative
							MI	Neutral
							Stroke	Neutral
							Stent placement	Neutral
Rosenblatt ^[9] N = 1,155	First line ART to alternative ART; HIV	Optum Research Database and Impact National Benchmark Database; Matched	Bristol-Myers Squibb	18 months	Yes	Clinical	Virologic failure	Neutral
							Next ART Change	Negative
						Economic	Inpatient costs	Neutral
							ER costs	Neutral
							Ambulatory costs	Neutral
							Other medical costs	Neutral
						Resource Utilization	Inpatient visits	Neutral
							Length of inpatient visit in days	Neutral
							ER visits	Neutral
							Ambulatory visits	Neutral
Wolf ^[10] N = 754	Anti-TNF to different anti-TNF; CD, UC, RA, AS, PS, PsA	Gastroenterologist, rheumatologist, and dermatologist chart review at multiple sites; Matched	Abbvie	12 months	Yes	Clinical	Disease flares	Negative
							Well-controlled disease	Negative
						Resource Utilization	Inpatient visits	Negative
							ER visits	Negative
							Outpatient visits	Negative
Boktor ^[14] N = 60	Infliximab or Adalimumab to Certolizumab; CD	Louisiana State University Health Sciences Center EHR data; Pre/post	None	12 months	No	Clinical	ESR	Neutral
							CRP	Neutral
							Hemoglobin	Neutral
							Albumin	Neutral
							WBC	Neutral
							CDAI	Neutral
Yip ^[15] N = 521	Fluticasone/salmeterol to mometasone/ formoterol; COPD	Kaiser Permanente; Pre/post	None	6 months	No	Clinical	COPD exacerbation	Positive
							Required modification in therapy	Neutral
						Resource Utilization	Inpatient visits for COPD exacerbation	Neutral
							ED or urgent care visits for COPD exacerbation	Neutral
							Outpatient encounter for COPD exacerbation	Neutral
							ICU admission for COPD exacerbation	Neutral
Andreoli ^[16] N = 77^a	Ranibizumab to bevacizumab; Neovascular AMD	Harvard Vanguard Medical Associates EHR data; Pre/post	NR	10 months	No	Clinical	Mean Vision	Neutral
							Injections per year	Neutral
							OCT CSF thickness	Neutral
Asias ^[17] N = 133	Insulin glargine to insulin detemir; DM	VA; Pre/post	None	3-9 months	No	Clinical	Hemoglobin A1C	Negative
							Long acting insulin dose	Negative
							Weight	Positive
							BMI	Positive
Liu ^[24] N = 3,678	Adalimumab to different biologic (certolizumab, golimumab, etanercept, or ustekinumab); RA, PS, PsA, AS, CD	OptumInsight Database; Unmatched	Abbvie	6 months	Yes	Economic	All-cause medical costs	Negative
Low ^[18] N = 1,280	Atorvastatin to simvastatin; HLD	Massachusetts General Physicians Organization EHR data; Unmatched	None	12 months	No	Clinical	LDL	Neutral
Bryant ^[39] N = 31	Insulin glargine to insulin detemir; DM	Iowa academic medical center EHR data; Pre/post	NR	12 months	No	Clinical	Goal hemoglobin A1C	Neutral
							Weight gain	Neutral
							Hypoglycemia	Neutral
Saseen ^[25] N = 3,412	Olmesartan to different ARB; HTN	GE Healthcare’s Centricity EMR Database; Adjusted	Daiichi Sankyo	1-13 months	Yes	Clinical	SBP <140 mmHg	Negative
							DBP <90 mmHg	Negative
Alemayehu ^[40] N = 75,560	Esomeprazole to different PPI; Acid suppression	Ingenix LabRx Database; Unmatched	AstraZeneca	6 months	No	Economic	GI-related medical service costs	Negative
							Non-PPI prescription costs	Negative
Kamal ^[34] N = 258	ARB to different ARB; HTN	GE Healthcare’s Centricity EMR Database; Matched	Novartis Pharmaceuticals	6 months	Yes	Clinical	SBP	Negative
							DBP	Neutral
							Addition of other anti-HTN medications	Negative
						Resource Utilization	Office visits	Neutral
Signorvitch 2012 N = 6,270	Adalimumab to different DMARD; RA	MarketScan; Adjusted	Abbot Laboratories	6 months	Yes	Resource Utilization	ER visits	Negative
							RA outpatient visits	Negative
						Medication Taking Behavior	Discontinuation	Negative
West ^[36] N = 661	Psychiatric medications; Psychiatric conditions	Psychiatrist chart review at multiple sites; Matched	APF^b and AHRQ	12 months	Yes	Clinical	Adverse events (in patients switched to a medication within the same class)	Neutral
							Adverse events (in patients switched to an interchangeable medication in a different class)	Negative
Wu ^[37] N = 8,898	Brand SSRI to different generic SSRI; MDD	Ingenix Impact Database; Matched	Forest Research Institute	6 months	Yes	Economic	MDD-related medical cost	Negative
						Resource Utilization	MDD-related hospitalization	Negative
							MDD-related ER visits	Neutral
Signorvitch 2010 N = 102,076	Valsartan to different ARB; HTN	MarketScan; Matched	Novartis Pharmaceuticals	6 months	Yes	Economic	Total medical costs excluding ARB cost	Negative
							HTN-related medical services
							Inpatient costs	Negative
							ER costs	Neutral
							Outpatient costs	Neutral
							Non-ARB hypertensive drug cost	Neutral
						Resource Utilization	HTN-related medical services
							Inpatient days	Negative
							ER visits	Neutral
							Outpatient visits	Negative
						Medication Taking Behavior	Discontinuation	Negative
Miller ^[41] N = 117	Atorvastatin to simvastatin, rosuvatatin or ezetimibe-simvastatin; HLD	University of Colorado Healthcare System EHR data; Pre/post	NR	1-13 months	No	Clinical	LDL
							Usual care	Negative
							Conversion by pharmacist	Neutral
							HDL
							Usual care	Neutral
							Conversion by pharmacist	Neutral
							Triglycerides
							Usual care	Neutral
							Conversion by pharmacist	Neutral
Gates ^[27] N = 364	Fosinopril to benazepril; HTN	VA; Pre/post	NR	4 months	No	Clinical	SBP	Neutral
							DBP	Neutral
							Estimated GFR	Neutral
							Serum potassium	Neutral
Meissner ^[42] N = 3,636	Atorvastatin to different statins (simvastatin, lovastatin, pravastatin, or fluvastatin); HLD	Segment of multistate Medicaid MCO claims database; Pre/post	None	12 months	No	Economic	Statin therapy medical management costs	Neutral
Billlups 2005 N = 5,046	Simvastatin to lovastatin; HLD	Kaiser Permanente; Pre/post	None	≥1.5 months	No	Clinical	LDL	Positive
							ALT	Neutral
						Medication Taking Behavior	Adherence	Neutral
Cheetham ^[23] N = 33,318	Simvastatin to lovastatin; HLD	Kaiser Permanente; Pre/post	NR	3-15 months	No	Clinical	LDL	Positive
							HDL	Positive
							Triglycerides	Positive
							Marked ALT	Neutral
							Marked CK	Neutral
Tran ^[43] N = 32	Celecoxib or rofecoxib to valdecoxib; OA, RA, pain	VA patient interviews; Pre/post	NR	0.5 months	No	Clinical	Pain	Neutral
Manzo ^[29] N = 68	Amlodipine to felodipine; HTN	VA; Pre/post	AstraZeneca	6 months	No	Clinical	SBP	Neutral
							DBP	Neutral
							Heart rate	Positive
Graham ^[30] N = 72	Losartan or valsartan to irbesartan; HTN	VA; Pre/post	Bristol-Myers Squibb	2 months	No	Clinical	SBP	Neutral
							DBP	Neutral
							Heart rate	Neutral
							Adverse drug reactions	Neutral
Taylor ^[31] N = 942	Atorvastatin, fluvastatin, pravastatin, low-dose simvastatin (<80 mg/day) and cerivastatin (<0.4 mg/day) to cerivastatin (0.4 or 0.8 mg/day) or simvastatin (80 mg/day); HLD	Chart review at Walter Reed Army Medical Center; Pre/post	Bayer Pharmaceutical Corporation	1.5 months	No	Clinical	LDL	Positive
							HDL	Positive
Andrade ^[44] N = 2,235	Conjugated to esterified estrogen or different HRT medication; HRT	Fallon Community Health Plan HMO Claims data; Pre/post	Solvay Pharmaceuticals	6 months	No	Resource Utilization	Ambulatory visits related to HRT
							Switched to different HRT	Neutral
							Switched to esterified estrogen	Neutral
Clay ^[45] N = 113	Amlodipine to felodipine; HTN/angina	Chart review at Naval Health Clinic Charleston; Pre/post	NR	12 months	No	Clinical	BP <140/90 mmHg	Neutral
							Use of other anti-HTN medications	Neutral
Fugit ^[26] N = 96	Simvastatin to lovastatin; HLD	VA; Pre/post	NR	3 months	Yes	Clinical	Lipid tests	Neutral
							Liver function tests	Neutral
Good ^[32] N = 704	Nizatidine to cimetidine; duodenal and gastric ulcer disease, GERD	VA; Pre/post	NR	6 months	No	Resource Utilization	Clinic visits	Neutral
							GI-related admissions	Neutral
							Abdominal CT	Neutral
							Barium studies	Positive
							Endoscopic studies	Neutral
Mamdani ^[46] N = 101	Nifedipine extended-release to amlodipine or felodipine; HTN	VA; Pre/post	Astra-Merck	9 months	No	Clinical	SBP	Positive
							DBP	Positive
							Drug utilization (prescriptions for any medication/patient)	Negative
						Economic	Cardiovascular drug cost^c	Negative
							Non-cardiovascular drug cost	Negative
						Resource Utilization	Clinic visits	Neutral
							Emergency room visits	Neutral
							Hospitalizations	Neutral
Nelson ^[47] N = 105	Omeprazole to lansoprazole; heartburn, GERD	Interviews of patients identified in Unity Prescription Database; Pre/post	TAP Pharmaceuticals	1 month	No	Clinical	Heartburn symptom severity	Negative
							Overall patient satisfaction	Negative
Oatis ^[33] N = 142	Amlodipine to felodipine extended-release; HTN/angina	Chart review at Barksdale Air Force Base Pharmacy; Pre/post	NR	6-9 months	No	Clinical	Concomitant cardiovascular medications	Negative
						Economic	Concomitant cardiovascular drug cost	Negative
Parra ^[49] N = 100	Amlodipine to different CCB (felodipine; SR nifedipine, SR verapamil, SR diltiazem); HTN	VA; Pre/post	AstraZeneca	5 months	No	Clinical	SBP	Neutral
							DBP	Positive
							Pulse	Neutral
Walters ^[49] N = 44	Amlodipine to felodipine extended-release; HTN	VA; Pre/post	NR	2-6 months	No	Clinical	SBP	Neutral
							DBP	Neutral
							Heart rate	Neutral
							PR interval	Neutral
							QRS interval	Neutral
							QTc interval	Neutral

^aRepresents number of eyes treated.

^bAFP received financial support from a consortium of industry supporters.

^cExcluding prescriptions for the index therapy.

AHRQ = Agency for Healthcare Research and Quality; ALT = alanine aminotransferase; AMD = age-related macular degeneration; APF = American Psychiatric Foundation; ARB = angiotensin receptor blocker; ART = antiretroviral therapy; AS = ankylosing spondylitis; AST = aspartate transaminase; BMI = body mass index; BP = blood pressure; CCB = calcium channel blocker; CD = Crohn’s disease; CDAI = Crohn’s Disease Activity Index; CK = creatine kinase; COPD = chronic obstructive pulmonary disease; CPK = creatine phosphokinase; CSF = central subfield thickness; CT = computerized tomography; DBP = diastolic blood pressure; DM = diabetes mellitus; DMARD = disease-modifying antirheumatic drug; EHR = electronic health record; EMR = electronic medical record; ER = emergency room; ESR = erythrocyte sedimentation rate; GE = General Electric; GERD = gastroesophageal reflux disease; GFR = glomerular filtration rate; GI = gastrointestinal; HIV = human immunodeficiency virus; HDL = high density lipoprotein; HLD = hyperlipidemia; HRT = hormone replacement therapy; HTN = hypertension; ICU = intensive care unit; LDL = low-density lipoprotein; MAP = mean arterial pressure; MCO = managed care organization; MI = myocardial infarction; MDD = major depressive disorder; N = sample size; NMS = non-medical switch; NR = not reported; OA = osteoarthritis; OCT = optical coherence tomography; PPI = Proton Pump Inhibitor; PS = psoriasis; PsA = psoriatic arthritis; RA = rheumatoid arthritis; RWD = real-world data; SBP = systolic blood pressure; SR = sustained release; SSRI = selective serotonin reuptake inhibitor; TNF = tumor necrosis factor; UC = ulcerative colitis; VA = Veterans Affairs; WBC = white blood cell.

Figure 1. Flow Diagram of Study Selection Process*.

*”Not a study” refers to a citation that was excluded because it was not a primary literature source (e.g., review articles, editorials)

Table 3. Overall sub-classification of outcomes.

Outcome sub-classification	n (%)
Non-medical switch category
Category A (stable/well-controlled disease)	49 (31.8)
Category B (no requirement for stable/well-controlled disease)	105 (68.2)
Type
Clinical	93 (60.4)
Economic	24 (15.6)
Resource utilization	33 (21.4)
Medication taking behavior	4 (2.6)
Disease State
Cardio-metabolic	95 (61.7)
Immune-mediated disorders	23 (14.9)
Human immunodeficiency virus	10 (6.5)
Acid suppression	9 (5.8)
Other^a	17 (11.0)
Publication Year
2015-2018	65 (42.2)
2010-2014	28 (18.2)
2005-2009	19 (12.3)
2000-2004	42 (27.3)
Follow-up^b
≥6 months	97 (63.0)
<6 months	56 (36.4)
Entity conducting study
Performed by entity dictating non-medical switch	92 (59.7)
Not performed by entity dictating non-medical switch	62 (40.3)

^aOther included chronic obstructive pulmonary disease (n = 6), psychiatric (n = 5), age-related macular degeneration (n = 3), hormone replacement therapy (n = 2), pain (n = 1).

^b Duration of follow-up was not reported for one outcome.

Figure 2. Direction of Outcomes in All Studies and Stratified by Non-medical Switch Categories*.

*Panel I = all studies; II = category A studies; III = category B studies

Figure 3. Direction of Outcomes Stratified by Study Subsets.

NMS = non-medical switching panel I = Stratified by publication year; II = Stratified by follow-up*; III = Stratified by whether entity performed the non-medical switch*Duration of follow-up was not reported for one outcome.

Figure 1. Modified Newcastle-Ottawa Quality Assessment Scale Results by Non–medical Switch Category

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