Does Independent Scope of Practice Affect Prescribing Outcomes, Healthcare Costs, and Utilization?

Transcription

1 Does Independent Scope of Practice Affect Prescribing Outcomes, Healthcare Costs, and Utilization? AUTHORS Ulrike Muench 1,2,4, PhD, RN Janet Coffman 2,3,4, PhD, MPP Joanne Spetz 2,3,4, PhD 1 Social and Behavioral Sciences, School of Nursing, University of California San Francisco 2 Philip R. Lee Institute for Health Policy Studies, University of California, San Francisco 3 Department of Community and Family Medicine, School of Medicine, University of California San Francisco 4 Healthforce Center, University of California, San Francisco CONTACT Ulrike Muench, RN, PhD Assistant Professor Social and Behavioral Sciences, School of Nursing and Philip R. Lee Institute for Health Policy Studies University of California San Francisco (415) ulrike.muench@ucsf.edu OVERVIEW This issue brief reports early findings from a study of the effects of independent scope of practice (SOP) for nurse practitioners (NPs) on prescribing outcomes, healthcare costs, and prices for primary care services. KEY FINDINGS We found no increase in medication adherence that was associated with differences in NP SOP laws, or the passage of a new law allowing NPs independent practice and prescribing. Independent SOP was associated with 1-4% increase in health care costs in two of the three patient cohorts studied. Provider prices for primary care services fell by 1-4% following the implementation of independent SOP for NPs. SUMMARY Independent NP SOP may lead to a drop in prices for two reasons. First, if independent SOP increases NP supply, prices should decline. Second, a greater share of services might be provided by NPs in states with independent SOP 1, and NPs are generally less expensive than physicians 2. Increased total health care costs may be a result of increased volume in services, which may stem from increased access to care. Further research is necessary to establish the relationship between SOP and costs of care, and between SOP and patient outcomes. In this report we document the results of a study examining whether nurse practitioner (NP) state scope of practice (SOP) regulations affect prescribing outcomes, health care costs, and health care utilization. State SOP regulations determine whether a physician must be involved in the NP s care of patients and regulate the NP s ability to diagnose illness and prescribe medications. Understanding how these laws affect outcomes, costs of care, and utilization is important for the implementation of the ACA because they could directly affect access to care services and medications, thereby potentially impacting the quality and cost of health care. POTENTIAL ADVANTAGES OF INDEPENDENT NURSE PRACTITIONER PRESCRIBING Evidence suggests that states that successfully introduced independent NP SOP were able to increase the number of routine check-ups 3, lowered body mass index, and achieved a lower rate of ER admissions for conditions that are sensitive to ambulatory care 4. Research also suggests that restrictive scope-of-practice regulations may hinder the expansion of health care utilization when provider supply grows 3,5. ISSUE BRIEF 1

2 FIGURE 1 Medication Adherence Rate for 3 Major Therapeutic Categories Notes: Blue = States switching between Red = States without independent SOP between STATES AND SCOPE OF PRACTICE LAWS By 2012, 18 states had established independent SOP for nurse practitioners. During our study period from to 2012, 5 states implemented independent scope of practice laws: Hawaii, Colorado, Nevada, Vermont, and Maryland. Our study sought to examine whether states that switched to allowing NPs to practice and prescribe without the supervision of a physician from to 2012 were able to achieve better medication adherence rates, lower costs of care, and lower prices for primary care services. THE SAMPLE Our analysis used data from the Health Care Cost Institute, which included nearly 28 million individuals from all 50 states and the District of Columbia, ages 18-64, who were using renin angiotensin system antagonists (RASA), diabetes medications, or antihyperlipidemics and who were enrolled in employer-sponsored insurance for all 12 months of a coverage year. This population was selected based on a National Quality Forum measure approved to evaluate medication adherence in claims data 6. MEDICATION ADHERENCE DID NOT IMPROVE WHEN STATES CHANGED NP SCOPE OF PRACTICE Figure 1 shows the average medication adherence rate for each medication type, for states that implemented independent NP practice during the study period versus states that did not. The blue line represents states that passed a law granting NPs independent SOP between and 2012 and the red line indicates states that did not have independent NP SOP during this time. For both groups of states, medication adherence improved slightly over time. There was no statistically significant difference in the improvement of medication adherence from to 2012 between patients living in states that changed their NP SOP regulations than for those living in states that did not adopt independent NP SOP. We conducted further analyses that accounted for patient demographics, differences in insurance types, number of primary care providers in each state, and other factors that might affect patient adherence to medication utilization. However, controlling for those factors did not change the assessment that NP SOP regulations had no impact on medication adherence over this time period. Antidiabetics Renin Angiotensin System Antagonist Antilipidemics 85% 84% 83% 82% 81% 80% 79% 78% 86% 85% 84% 83% 82% 81% 80% 79% 78% 84% 83% 82% 81% 80% 79% 78% 77% 76% ISSUE BRIEF 2

3 Cost difference SOP / no SOP Pts on anti-diabetics Pts on RASA Pts on anti-hyperlipedemics Statistical significance Cost difference SOP / no SOP Statistical significance Cost difference SOP / no SOP Statistical significance Inpatient N/A Not significant N/A Not significant N/A Not significant Outpatient N/A Not significant $144 Significant -$165 Significant Physician N/A Not significant $102 Significant $161 Significant Rx N/A Not significant $74 Significant N/A Not significant Total N/A Not significant $271 Significant $289 Significant TABLE 1 Effect of Independent Scope of Practice on Costs Note: Statistical significance is reported at the <.05 level TABLE 2 Price Differences for Primary Care Services Between States that Implemented Independence and States that Did Not Note: Statistical significance is reported at the <.05 level INDEPENDENT SCOPE OF PRACTICE IS ASSOCIATED WITH INCREASES IN COSTS OF CARE WHEN ADJUSTING FOR PATIENT AND STATE CHARACTERISTICS Average costs of care are shown for inpatient, outpatient, physician, pharmacy, and total costs in Figure 2. Even though states that implemented independent SOP had lower average total costs of care (blue line) compared to states that do not have independent practice (red line), independent SOP states did not significantly reduce costs between and 2012 compared to states that do not have independent SOP. When we adjusted the analysis for patient demographics, insurance type, and other state characteristics, cost increases were observed for outpatient, physician, pharmacy, and total costs for patients on RASA, and for physician and total costs for patients on statins. There were no cost changes associated with SOP changes for patients on diabetes medications. Predicted cost differences ranged from $74 to $289 (see Table 1), or a 1 to 4% increase from the mean estimated costs summarized in Figure 2. Primary Care Service Type PROVIDER PRICES FOR PRIMARY CARE SERVICES FELL WITH INDEPENDENT SCOPE OF PRACTICE Figure 3 illustrates average provider prices from NPs and physicians for common primary care services. For the purpose of this analysis we selected outpatient visit types of minimal to low severity and adult preventative visits for ages 18 to 64, assuming that these services are most likely to be carried out by both physicians and NPs. Thus, these are services for which there was likely an increase in market competition following a change in NP SOP regulation, because having independent NP SOP may increase the amount of visits provided by NPs and possibly increase NP supply. Figure 3 shows that changes in average prices did not differ significantly between states that implemented independent NP SOP versus states that did not. However, after adjusting for patient and state characteristics, we found a drop in prices for all services, except one. The one service type that did not see a lower price was related to a billing code primarily used by NPs and which might not be exposed to the same degree of market competition as services that are provided by both NPs and physicians. Difference SOP / no SOP (in dollars) Statistical significance Established Patient Minimal Severity Not significant Established Patient Minor Severity Significant Established Patient Low/Moderate Severity Significant Adult Well Visit Years Significant Adult Well Visit Years Significant ISSUE BRIEF 3

4 FIGURE 2 Average Costs for Patients Notes: Blue = States switching between Red = States without independent SOP between Inpatient Costs Antidiabetics RASA Antilipidemics Outpatient Costs Physician Costs Prescription Costs $3,500 $3,500 $3,500 Total Costs $10,500 $10,500 $10,500 $9,500 $9,500 $9,500 $8,500 $8,500 $8,500 $7,500 $7,500 $7,500 ISSUE BRIEF 4

5 FIGURE 3 Primary Care Service Type Notes: Blue = States switching between Red = States without independent SOP between Established Patient Visit Severity Minimal Established Patient Visit Severity Minor Established Patient Visit Severity Low/Moderate $40 $60 $80 $30 $50 $70 $20 $40 $60 $10 $30 $50 Preventative Adult Visit Years Preventative Adult Visit Years $130 $140 $120 $130 $110 $120 $100 $110 SUMMARY This study observed a small increase in total costs of care and a small decrease in prices for primary care services in states that implemented independent NP SOP between and 2012, as compared with states that restricted NP SOP throughout this period. Medication adherence did not change during this time. We conclude that independent NP SOP may lead to a drop in prices, perhaps through increased NP supply and changes in service provision between NPs and physicians. The increase in total costs may be related to an increase in volume of services provided by NPs, which may result from increased access to care if independent SOP leads to growth in NP supply. Further research is necessary to establish the relationship between SOP and costs of care, and between SOP and patient outcomes. ISSUE BRIEF 5

6 While our findings suggest that changing NP SOP has no effect on medication adherence and limited effects on prices and costs, SOP still might be important for other patient or provider behaviors or outcomes. Previous research suggests that independent SOP for nurse practitioners can positively affect health care outcomes. Medication adherence is affected by multiple factors and may not be as responsive to changes in SOP laws as some other patient behaviors or outcomes. States should carefully consider the potential effects of changing SOP for access to care, prices, and outcomes. REFERENCES 1. Kuo Y-F, Loresto FL, Rounds LR, Goodwin JS. States with the least restrictive regulations experienced the largest increase in patients seen by nurse practitioners. Health Aff Proj Hope. 2013;32(7): doi: /hlthaff Perloff J, DesRoches CM, Buerhaus P. Comparing the Cost of Care Provided to Medicare Beneficiaries Assigned to Primary Care Nurse Practitioners and Physicians. Health Serv Res. December 2015:n/a - n/a. doi: / Stange K. How does provider supply and regulation influence health care markets? Evidence from nurse practitioners and physician assistants. J Health Econ. 2014;33:1-27. doi: /j.jhealeco Traczynski J, Udalova V. Nurse Practitioner Independence, Health Care Utilization, and Health Outcomes Xue Y, Ye Z, Brewer C, Spetz J. Impact of state nurse practitioner scope-of-practice regulation on health care delivery: Systematic review. Nurs Outlook. doi: /j.outlook National Quality Forum. Proportion of Days Covered (PDC): 3 Rates by Therapeutic Category. gl/mjydac. Accessed November 1, This research product, using HCCI data, was independently initiated by the researchers and is part of the State Health Policy Grant Program funded by the Laura and John Arnold Foundation. ISSUE BRIEF 6