Improving Immunization Rates in a Hospital-Based Primary Care Practice

Setting

The initiative began in September 2009 at a hospital-based pediatric primary care practice in Boston, Massachusetts. The practice serves a patient population of 14 000, with more than 40 000 clinical encounters annually. Patients reside primarily in the urban neighborhoods of greater Boston, and 65% are Medicaid insured. The pediatric provider staff includes 65 resident physicians, 25 attending physicians, and 4 nurse practitioners. The nursing to provider ratio is 0.75 nurse full-time equivalent (FTE) to each provider FTE. Nurses routinely screen for immunization needs and administer vaccines.

Multidisciplinary Improvement Team

The improvement team included 1 physician, 1 departmental QI director, 1 nurse manager, 1 staff registered nurse, 1 social worker, and 1 quality improvement assistant (QIA). The QIA was an existing administrative staff member identified to take a leadership role in QI activities. The QIA specifically maintained the patient-tracking registry and performed patient outreach and care coordination activities. Though not part of the core improvement team, residents were a primary referral source for the QIA regarding the tracking registry. We regularly provided educational briefings and opportunities for residents to connect with the QIA during clinic sessions.

Planning the Initiative

Our team conducted monthly practice-wide evaluations of immunization rates for children age 24 months. We created statistical process control charts using monthly rate data, which provided a visual representation of progress over time. We then modified the monthly rates to exclude vaccine refusals and practice transfers. The QI director designed flowcharts to clarify the process of immunization assessment and delivery across the practice. Using the flowcharts, we generated 3 core interventions: systematic identification and capture of target patients, use of a patient-tracking registry, and patient outreach and care coordination. Figure 1 outlines the key drivers, and Fig 2 illustrates specific timeline components of the initiative.

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FIGURE 1

Key driver diagram.

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FIGURE 2

Control chart for overall immunization rates for patients aged 24 months, study period January 2009 through December 2012.

Implementing the Initiative

The initiative consisted of 3 primary interventions targeting underimmunized patients aged 15 to 23 months. We targeted the 15- to 23-month age range as a window of opportunity for immunization by 24 months.

Intervention 1: Systematic Identification and Capture of Target Patients

We used our homegrown immunization database to generate monthly reports for all patients across the practice in the target age range. We manually reviewed the reports and added any patients identified as underimmunized to the tracking registry. To capture patients at the point of care, we programmed the scheduling software (EPIC, Verona, WI) to highlight 15- to 23-month-olds regardless of visit type. The highlighted field activated front desk staff to place a bold “Check Immunizations” stamp on the visit billing sheet. The stamp served as a visual reminder for nurses and providers to assess immunization status and administer necessary vaccines. Any target patients not receiving vaccines at the point of care could be referred to the QIA for entry into the tracking registry. We expanded this process to include urgent care and walk-in visits (Fig 1).

Intervention 2: Use of a Patient-Tracking Registry

We used Excel software (Microsoft Corporation, Redmond, WA) to build a tracking registry for underimmunized patients 15 to 23 months of age. We designed the registry to facilitate care coordination aimed at bringing underimmunized patients up to date. The registry’s initial fields included date of patient identification, action plan for care coordination, and date of action follow-through. We refined the registry to include action plan fields for difficult-to-reach patients and non–English-speaking families. We also honed the action plan fields to incorporate follow-up attempts, their outcomes, and anticipated date of next attempt. The QIA managed the registry and performed care coordination activities. We also trained the QIA on appointment scheduling to facilitate care coordination during patient outreach (Fig 2). Social work and interpreter services were available for consultation as needed. The improvement team met weekly to review progress and troubleshoot challenging cases.

Intervention 3: Patient Outreach and Care Coordination

In general, the QIA attempted outreach 3 times to coordinate care for immunization follow-up. The QIA mailed letters for patients not reachable by phone. Each outreach attempt was entered into the patient-tracking registry along with reminder dates for the next attempt. In successful attempts, the QIA scheduled follow-up appointments for immunizations while on the phone. These appointments often coincided with due or overdue well child care and were scheduled accordingly. The QIA notified pediatric providers via e-mail about the upcoming appointments and offered suggestions about which vaccines to order (Fig 2). The QIA also flagged pending appointments in the scheduling program to include the suggested vaccines (Fig 2). After the appointment, the QIA reviewed the medical record to confirm receipt of vaccines. Patients not receiving the necessary vaccines remained in the tracking registry for subsequent care coordination. The QIA followed up on missing outside immunization records and added patients still designated as underimmunized to the registry. No patient exited the registry until he or she was confirmed as up to date or transferred out of the practice.

QIA Training and Use

We used the QIA at 0.5 FTE, or ∼20 hours per week during early implementation. Although the QIA was a single person, we trained multiple administrative staff on the QIA roles, including registry maintenance and patient outreach. The QIA roles were administrative by nature and therefore easily adopted. Training multiple staff distributed the FTE among existing personnel and created a failsafe in the event of staffing changes, vacation, or sick time. As the initiative progressed, the number of underimmunized patients needing tracking and care coordination decreased. By 6 months we were able to reduce QIA effort to 4 to 5 hours per week, which we have sustained to the present day.

Evaluation

To evaluate the initiative, we measured monthly immunization rates for patients aged 24 months across the practice. We considered patients immunized only if they received the full 4:3:1:4:3:1:4 vaccine series by their second birthday. We measured both overall immunization rates and modified rates, which excluded vaccine refusals and practice transfers. We plotted monthly overall and modified immunization rates on statistical process control charts. We established a mean immunization rate, illustrated as the center line (CL) on each control chart. We also established upper control limits and lower control limits on each control chart. These limits constrain common cause variation, or noise, within the system. We monitored the monthly data for special cause variation, illustrated on the control charts by 6 or more consecutive points above the CL. Special cause variation signals an effect and indicates a system change.

We used χ² tests to evaluate differences in immunization rates before and after implementation of the initiative. We conducted subanalyses to examine differences in immunization rates based on pediatric provider type, demographic characteristics, and insurance coverage. We used descriptive statistics to characterize actions taken on special cases to bring patients up to date. The initiative was categorized as QI and exempted from review board approval at our institution.