Available online at www.sciencedirect.com

S E M I N S P I N E S U R G 2 6 ( 2 0 1 4 ) 2 – 7

1040-7383/$ - see frohttp://dx.doi.org/10.

nCorresponding auE-mail address:

www.elsevier.com/locate/semss

Cost-effectiveness, QALYs, and incrementalcost-effectiveness ratios

Ravi R. Patel, MDa, Todd J. Albert, MDb, and Jeffrey A. Rihn, MDb,n

aDepartment of Orthopaedic Surgery, Emory University Hospital, Atlanta, GAbDepartment of Orthopaedic Surgery, Thomas Jefferson University Hospital, The Rothman Institute, 925 Chestnut St, 5th Floor,Philadelphia, PA

a b s t r a c t

The cost of healthcare in the United States has

Spine care has not been immune to these el

environment, policy makers and payers have s

of value-based healthcare. Spine care providers

treatments that they provide. This manuscr

healthcare, outcomes measures, and cost-effec

our future practice.

nt matter & 2014 Elsevie1053/j.semss.2013.07.003

thor.jrihno16@yahoo.com (J.A

continued to grow at an unsustainable rate.

evating costs. Given the current economic

tarted to consider a move towards a system

will be required to measure the value of the

ipt discusses the concepts of value-based

tiveness and the influence they will have on

& 2014 Elsevier Inc. All rights reserved.

1. Introduction

The cost of healthcare in the United States has continued togrow at an unsustainable rate. Emerging technology and anincreased demand from an aging population have contrib-uted to higher costs. Greater expenditure, however, does notnecessarily translate into improved care. Although the UnitedStates spends more on healthcare than any other industrial-ized nation, it ranks only 37th out of 191 countries in theoverall performance of the healthcare system.1 Spine carehas not been immune to these elevating costs and its valuehas become an increasing focus for policy makers andphysicians.Back and neck pain are among the most common com-

plaints encountered in clinical practice. Low back pain aloneaccounted for approximately 2% of all physician officevisits.2 Rates of imaging, injections, opiate use, and surgeryfor spine problems have increased substantially over thepast decade.3–6 Spine care-related expenditures totaled $86billion in 2005, representing a 65% increase from 1997.2 Thisincrease in cost did not, however, translate into improvedhealth status.2

r Inc. All rights reserved.

. Rihn).

Given the current economic environment, policy makersand payers have moved towards a system of value-basedhealthcare. This concept involves cost-cutting of course, butalso achieving the greatest quality of care for the leastmoney. A value-based healthcare system may have advan-tages over the traditional fee-for-service medicine that hasbeen practiced. Concentrating solely on cost may be detri-mental and would ignore the altruistic purpose of medicine,resulting in cost-shifting rather than cost-saving. There isalso the concern of spurring increased clinical volume inresponse to decreasing reimbursement. The economic crisisfacing our country demands that reform consider both costand quality.In light of this, it is reasonable to expect that spine care

providers will be required to measure the value of the treat-ments that they provide. The Patient Protection and Afford-able Care Act passed in 2010 is expected to investigatepayment for healthcare services as related to clinical out-comes.2 The legislation established the Patient-Centered Out-comes Research Institute, whose board is comprised ofpatients, doctors, hospital executives, drug makers, devicemanufacturers, insurers, payers, government officials, and

S E M I N S P I N E S U R G 2 6 ( 2 0 1 4 ) 2 – 7 3

health experts. Its purpose is to examine the relative healthoutcomes, clinical effectiveness, and appropriateness of dif-ferent medical treatments by evaluating existing studies andconducting its own. This is particularly applicable to spinecare, a field where the use of new devices and biologics hasbeen commonplace even though the benefits or the relativeadvantages over existing technologies have not all beenclearly defined.7 For this reason, it is important for the spinecare provider to understand the concept of value as itpertains to spine care delivery and the methods in whichvalue can be determined.

2. Value-based healthcare

How does one define value? It is a very encompassing andabstruse term that is applied to many aspects of our lives. Inregards to healthcare, value may be defined as the quality ofan intervention divided by the cost of the interventionmeasured over time. Although superficially simplistic, thisequation is very complex and even the individual variablesare difficult to quantify. Several methods have been proposedto measure quality of care, including outcome measures(disease specific or general), process of care measures, safetymeasures, and patient satisfaction measures. Both direct costand indirect cost should be considered when measuringvalue. A cost-effectiveness analysis essentially combinesthese measures as cost divided by some measure of benefit.In the following sections, we will review the methods foroutcome assessment as well as the measurement of cost andvalue of spine care.

3. Outcome measures

Several spine care-related process of care measures andoutcome measures are currently used to assess quality, buteach has its downsides and limitations. The ideal outcomemeasure should be patient-focused and assess the effects ofan intervention that are most important to the patient(i.e., pain, function, and return to work or previous level ofactivity). It should be reliable, valid, simple to collect, simpleto score, and allow comparison of effectiveness across otherdisease states. Furthermore, measurements should be able tobe effectively communicated amongst the various partici-pants in healthcare delivery system (i.e., physicians, legisla-tors, patients, and the global payer community). With fewexceptions, medical professionals do not routinely measuretheir clinical outcomes. And this must change if we are tomeasure the quality and the value of the care we provide.A notable challenge to outcome studies is determining the

clinical significance of a change or difference in a health-related quality-of-life measure. An outcome questionnairewill report a numerical score and statistical analysis can bereadily performed. But the question arises whether a stat-istical improvement translates to an improvement in apatient sense of health or well-being. The minimal clinicallyimportant difference (MCID) has been defined as the smallestchange in outcome measures that the patient considersmeaningful.8 Although beyond the scope of this publication,

recent studies have been performed to investigate MCID as itrelates to disorders of the spine.8–11 The goal of treating apatient, however, is not to obtain a minimal clinical improve-ment. Thus, the idea of substantial clinical benefit (SCB) hasalso been proposed as a benchmark for outcome measuresused in spine-related research. Values for SCB in the settingof cervical fusion have been defined for the Neck DisabilityIndex (NDI) (9.5), SF-36 physical component summary score(6.5), and numeric rating scales for neck and arm pain (3.5).12

Values for SCB in the setting of lumbar fusion have beendefined for the Oswestry Disability Index (ODI) (18.8), SF-36physical component summary score (6.2), and numeric ratingscales for back and leg pain (2.5).13

3.1. Process measures

Process measures evaluate various aspects of patient carebefore, during, and after a treatment is provided to a patient.These measures are typically hospital-based measuredrecorded in electronic databases. Examples include operativetime, length of hospital stay, infection rate, the use ofappropriate perioperative antibiotic or thromboembolic pro-phylaxis, complications, readmission, and reoperations.These values are binary or numerical, and therefore areeasily recorded, stored, and understood. Furthermore, theyare considered free of bias that is encountered with patient-reported outcome measures. Process measures form thefoundation for the current Physician quality reporting initia-tive (PQRI) measurements required by the US govern-ment.14,15 These measures are currently used by hospitals,payers, and third party physician and hospital graders (e.g.,Health grades) to evaluate quality of care.It is unclear and unlikely, however, that process measures

are able to truly reflect the quality of care a patientreceives.14,15 Although they are important, these measuresare not patient-centered in that they do not address thosethings that are most important to the patient (i.e., pain andreturn to work or play). For instance, does decreased averageoperative time or hospital length of stay translate intoimproved patient function and satisfaction? It seemsunlikely. Process measures can be obtained with ease, andthe mere accessibility may cause policy makers and payers tomake inappropriate quality-of-care extrapolations. It is ourresponsibility as spine care clinicians to ensure that processmeasures are not the only measures that are used to gradeperformance or to make payment and coverage decisions.

3.2. Disease-specific measures

As the name implies, disease-specific measures assesshealth-related quality-of-life measures in patients afflictedby a particular pathologic process. Spine disease-specificmeasures relate to an injury (i.e., fracture), disease (i.e., spinalstenosis), or anatomic area (i.e., lumbar spine).16 For example,the Oswestry Disability Index (ODI) is a disease-specificmeasure intended to measure how a disorder of the lumbarspine affects the patient's function.17

Disease-specific measures have several reported advan-tages.18 The assessment poses questions that are tailored toa specific condition, as compared to general health measures

Fig. 1 – Chart showing the comparison of utility to time andthe calculation of QALYs.

S E M I N S P I N E S U R G 2 6 ( 2 0 1 4 ) 2 – 74

that ask general questions about a patient's overall healthand function. They have a high specificity and relevance to aspecific disease or anatomic region of the body. This producesa better ability to detect important and more subtle changesthat occur in the treatment of a disease over time.19–23 Also,because the instrument is disease-specific, patients may bemore accepting and responsive to the data collection.18

Disease-specific measures also have limitations. The assess-ment cannot be administered to patients who do not have therelevant disease or health condition.16 In addition, it does notallow comparison between outcomes of different treatmentsfor patients with different diseases. This is a hindrance whentreatment regimens want to be compared for the purpose ofresource allocation.16,24 It is also possible that the onlyavailable disease-specific measure is in fact not fully specificto the disease in question. For example, a low back painassessment tool may be too generalized and/or not necessa-rily account for the various etiologies of low back pain and thevarious treatment options available.16 Finally, disease-specificmeasures cannot typically be used in the value equationbecause they cannot directly calculate quality-adjusted lifeyears (QALYs). However, several disease-specific measureshave recently been converted to utility measures so thatQALYs can be calculated; the conversions of the ODI and theNDI to the SF-6D are examples.12,25

3.3. General health measures

General health measures assess the overall health of thepatient. General measures are designed to be used acrossdifferent diseases and across different demographic andcultural subgroups.16 They give a comprehensive and generaloverview of health-related quality of life. The most well-known general health measure is the SF-36, which wasdeveloped from the Medical Outcomes Study and has under-gone extensive analysis and validation.26,27 General healthmeasures allow comparison across various diseases states,can be used to calculate QALYs and cost-effectiveness, andare more likely to detect unexpected effects of an interven-tion.16,19,28 The limitation of general health measures is thatthey tend to be less responsive to changes in health statusthan disease-specific measures. Therefore, they are less likelyto detect the effects of a particular intervention.16,20,21

3.4. Utility measures

Utility measure refers to the desirability or preference thatindividuals exhibit for a particular condition. It can bethought of as a cardinal measure of the strength of one'spreference.29 The decisions are made under uncertainty,based on a set of axioms of rational behavior. In a healthcareapplication, they can be used to measure quality of life.There are several methods of deriving utility directly. The

standard gamble and the time trade-off methods are the twomost commonly used in healthcare. With the standardgamble method, the patient is asked to compare a life in agiven suboptimal health state to a gamble between theprobabilities (p) of two alternative outcomes, perfect health(p) or death (1�p).30 The variable p is varied until the patient isindifferent to the choice between the given health state and

the gamble.30 The time trade-off method asks the patient tocompare a length of life in a perfect state of health to thelength of life with a given health state. Using these methods,utility can be assigned to numerous health states, with scoresranging from 0 (death) to 1 (perfect health). The Euroquol-5D(EQ-5D), the Health Utility Index, and the SF-6D are indirectmeasures of utility that can be used to assess health out-come.12,25,30–32 These are less cumbersome to use comparedto directly measuring utility. They are questionnaire formsthat the patient fills out, with a utility score calculated usingan algorithm that is based on the answers to the questions onthe form.The utility approach has the advantage of providing a

single measure of quality of life that can be used forcomparison across different disease states and can be usedin cost-effectiveness research through the calculation ofQALYs.29 It can be, however, a time-consuming process,particularly if the time trade-off technique or the standardgamble method is used. Moreover, there are still methodo-logical issues that are not fully resolved, such as whoseutilities should be measured.29

3.5. Quality-adjusted life years (QALYs)

Quality-adjusted life years (QALYs) has become increasinglyused as a healthcare outcome measure and as an integralpart of cost–utility analysis.33,34 QALY is a measure of thevalue of a treatment. It combines length of life and quality oflife into a single index number.35 It is calculated as the areaunder the curve when measuring utility over time33 (Fig. 1).QALYs can be incorporated with medical costs to thencompare the cost-effectiveness of a treatment.33 This calcu-lation is based on the idea that the quality of life can bequantified as “utility.”34 Utility can be thought of as thepreference for a particular health state: the greater thepreference, the greater the utility associated with it.33 Asdescribed above, utility is expressed on a numerical scaleranging from 0 to 1, with 1 representing the utility of perfecthealth and 0 representing the utility of death. The utility ofa specific state of health can be estimated using a seriesof techniques such as standard gamble or time trade-offmethod, or by using an indirect utility measurement tool(i.e., SF-6D and EQ-5D).33,35

QALY calculation assumes that a year of life lived in perfecthealth is worth 1 QALY (1 year of life � 1 utility ¼ 1 QALY).

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Likewise, a year of life lived in a state of less than this perfecthealth is worth less than 1. To determine the QALY value,multiply the utility value of a particular state of health bythe years lived in that state. QALYs are therefore expressedin terms of “years lived in perfect health”: half a year livedin perfect health is equivalent to 0.5 QALYs (0.5 years� 1 utility), the same as 1 year of life lived in a situationwith utility 0.5 (e.g., bedridden) (1 year � 0.5 utility).33,34

4. Cost

The denominator for the value equation is cost. Healthcarecost calculation is challenging and there is significant varia-bility in the methodology of estimating direct and indirectcosts.36 The absence of a standard method to measure costsmakes it difficult to perform cost-effectiveness studies forspine diseases and spine care.36

4.1. Direct cost

Direct costs describe the costs that are the immediate resultof patient care. This includes the variables that one wouldexpect: clinic visits, surgical fees, anesthesia fees, hospitalfeeds, rehabilitation fees, etc. Unfortunately, the calculationis much more difficult than it should be. There is substantialvariability in costs for the same product/service depending ongeographical area and company contracts. Records of caredelivery may be difficult to interpret or acquire, leavingpatient recollection as the only source to determine utiliza-tion of services.

4.2. Indirect cost

Indirect costs, as one would presume, refers to the acquiredcosts that are not directly related to patient care. Thisprimarily refers to the cost to society that is incurred by lossof productivity related to a certain health condition or treat-ment. Additional indirect cost is accrued when family mem-bers or friends take time-off from work to care for a patient.The calculation of indirect cost is further complicated by thetemporary reduction in productivity a patient may have afterreturning to work; this would be very difficult to calculate andaccount for.The human capital approach is the most common method

for estimating indirect cost, specifically money lost from theloss of productivity.37 The calculation is determined by multi-plying the time-off of work by the sum of the wages andbenefits that patient typically receives. If the patient neverreturns to work, a friction cost is added that accounts for thetime it takes an employer to hire a replacement.36

5. Cost-effectiveness and ICERs

Cost-effectiveness analysis as applied to health economicsprovides an approach to medical decision making. A cost-effectiveness analysis is a type of economic evaluation inwhich cost is expressed over some unit of benefit (life yearsgained, symptom free months, etc.). A cost–utility analysis is a

type of cost-effectiveness analysis in which the benefit isexpressed in utility. The most commonly used measure ofbenefit in a cost–utility analysis is the QALY. In 2006, theUnited States Panel on Cost-Effectiveness in Health andMedicine published recommendations regarding cost-effectiveness research.38,39 The authors recommended thatcost-effectiveness research1 be performed from the societalperspective (i.e., using both direct and indirect costs),2 use autility score as the measure of benefit,3 appropriately discountboth cost and health benefit at the same rate, and4 includeappropriate incremental comparisons to allow for calculationof an incremental cost-effectiveness ratio (ICER) (e.g., compar-ing a surgical treatment to a nonsurgical treatment option).The ICER is the ratio of the change in costs to the incrementalbenefits of a treatment. Mathematically, it can be described asICER ¼ (C1�C2)/(E1�E2), where C1 and E1 are the cost andeffect in the intervention or treatment group and where C2and E2 are the cost and effect in the control care group. Cost isa monetary unit and effect can be measured in QALYs gainedor lost. In Great Britain, the National Institute for Health andClinical Excellence (NICE) has a willingness to pay thresholdthat ranges between £20,000 and £30,000/QALY gained.40

Treatments that have a reported cost/QALY ratio that isgreater than this threshold are not paid for by the insurer.In the United States, there is no standard willingness to paythreshold, although values of $50,000–$100,000/QALY gainedhave been used as thresholds.41 However, the concern forrationing of healthcare has led the US senate to forbid thePatient-Centered Outcomes Research Institute from usingcost/QALY or similar measure that discounts the value of alife because of an individual’s disability.42

Using 2-year follow-up data from the Spine Patient Out-comes Research Trial (SPORT), Tosteson et al.43,44 havereported on ICERs for the surgical management of lumbardisc herniation, lumbar stenosis, and degenerative spondy-lolisthesis. The authors compared the cost/QALY gained forsurgical management to nonoperative management of theaforementioned conditions. The reported cost per QALYgained with surgical treatment of lumbar disc herniationwas $69,403 when the non-Medicare rate was used to esti-mate surgical cost and $34,355 when the Medicare paymentrate was used to estimate surgical cost.43 The reported costper QALY gained with surgical treatment of spinal stenosiswas $77,600, and the reported cost per QALY gained withsurgical treatment of stenosis with degenerative spondylolis-thesis was $115,600.43,44 A more recent analysis by Tostensonet al.45 included the 4-year follow-up data from SPORT. Thecost/QALY gained for surgical management of disc herniationdecreased from $34,355 at 2-year follow-up to $20,600 at4-year follow-up; the cost/QALY gained for surgical manage-ment of stenosis decreased from $77,600 at 2-year follow-upto $59,400 at 4-year follow-up; and the cost/QALY gained forsurgical management of degenerative spondylolisthesisdecreased from $115,600 at 2-year follow-up to $64,300 at4-year follow-up. Because the improvement in utility overbaseline is durable for these three lumbar conditions up to4-year follow-up, the value of surgery for these conditionsimproved with longer-term follow-up. This point emphasizesthe need for an adequate time horizon when performing cost-effectiveness research.

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6. Conclusion

The current economic environment and the escalating cost ofhealthcare require us to assess our outcomes and the value ofour care. Back and neck pains are and will likely continue tobe among the most common complaints encountered inmedicine, as well as a target for healthcare payers and policymakers as expensive disorders to manage. It is very possiblethat our reimbursement will be tied to the value of the carewe provide. And it is our responsibility to ensure that themeasurements for calculating outcome and value are fullyunderstood and appropriate.

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