Table 1.

Descriptive table summary of the studies that used data derived missed opportunity for clinical or preventative service or procedure. Observational, review and interventional studies in any clinical topic area are included

Study purpose; Population and setting; Service or procedure; Timeframe; Location	Methodology (study design, health IT use, how the data were obtained)	Missed opportunity definition (data elements used; formula or other for deriving the value for missed opportunities)	Significant results or observations	Methodological advantages or limitations
Nowalk, et al., 2004 [8]
Purpose: To identify missed opportunities and find documentation of immunizations in medical records. 810 participants age ≥ 66 years are enrolled from 3 health centers located in disadvantaged neighborhoods. Sites include 3 VA clinics; 8 rural practices; 9 rural/urban clinics, all belonging to the same health network. Service: Adult immunizations (influenza, pneumococcal, tetanus) Review of visit data: 1998–2000 for influenza; 1995–2000 for PPV and tetanus Location: USA	Retrospective review of paper medical records. Exclusion criteria for review: patient data were excluded if the date of the first visit was after the recorded date of the vaccine receipt or if the patient was not seen during the review period (i.e., 1998–2000 for influenza; or 1995–2000 for PPV/tetanus)	For Tetanus and PPV: Administered to all patients without recorded vaccination: missed opportunities = total visits minus any visits in which vaccine was discussed or refused. For Influenza: visits during October–February where influenza vaccine was not given, discussed or refused.	Immunization rates were 24.1% for annual influenza, 49.1% for pneumococcal polysaccharide and 28.6% for tetanus vaccine. During the 27-month study period, patients averaged 1.3 +/− 1.9 acute visits, 6.9 +/− 5.1 chronic visits and 0.48 +/− 0.91 preventive visits (mean +/− S.D.). Missed opportunities to vaccinate ranged from 38.4 to 94.5% of visits.	Advantages: elucidated disparities in rates of missed opportunity amongst clinic type and setting (e.g., disadvantaged urban vs. suburban); good description of how missed opportunity were determined based on the visit and its outcomes. Limitations: retrospective medical record review period for influenza was shorter than other vaccinations - limits comparisons; study was conducted before electronic medical records were generally available
Singleton, et al., 2005 [11]
Purpose: To assess influenza and pneumococcal immunization rates (and racial disparities thereof) by telephone interview of adults age 65+. 1839 adult respondents (age 65+) completed a telephone questionnaire. Service: Influenza and pneumococcal vaccinations Timeframe for Influenza: 2002–2003 season; timeframe for pneumococcal questions: “recently, or ever, vaccinated” Location: USA	Interview of respondents reporting past vaccinations via telephone	Missed opportunity = had doctors visit, but did not receive a flu shot or a recent recommendation for one Data used to classify M missed opportunity O: clinic visit dates, vaccination status, physician recommendations for vaccination, knowledge of vaccine recommendations	67.8% had influenza vaccine in 2002–03 season; 60% had ever received pneumococcal (range 44% - 63%, depending on race, which was a significant predictor of vaccination status). Missed opportunity rates (recent doctor visit and vaccine recommendation from provider, but no vaccine): blacks, 26.9% versus 7.9%; Hispanics, 19.9% versus 12.1%; and white non-Hispanics, 16.2% versus 6.1%.	Advantages: good geographic spread of respondents (i.e., sampled from across USA); collected data on reasons for vaccination refusal; the results were concordant with those of other national surveys Disadvantages: study relied on patient-reported data; known confusion with pneumococcal vaccination among respondents; did not directly measure actual opportunities for, or refusals of, vaccination; recommendation date is necessarily limited to what the patient remembers/were aware of (e.g., doctors may have neglected/chose not to share recommendation with patient)
Weightman, et al., 2003 [13]
Purpose: To determine number of missed opportunities 101 patients ages 3 months - 97 years (mean = 63.5), enrolled after being admitted to hospital with a pneumococcal infection. Service: Pneumococcal vaccination Timeframe: 1990–1999 Location: UK	Retrospective manual review of hospital records; consultation with patients’ primary care providers; archived notes (deceased patients only)	Surveyed patients admitted to hospital with pneumococcal infection. If it was found that a patient was not vaccinated, investigators followed up with their primary care physician (and hospital encounters, if applicable) to determine number of missed opportunities (opportunity for vaccination defined as: in the 5 years preceding hospital admittance, patient had one or more of: family physician consult; attended hospital outpatient department; have been admitted to hospital).	Vaccination rate of 5% in those where an opportunity existed Missed opportunity: 30/101 (29.7%)	Disadvantages: patients resided in UK (likely have different guidelines); small sample size (n = 101)
Kyaw, et al., 2006 [9]
Purpose: To characterize vaccination status and opportunities for vaccination patients who had been hospitalized with invasive pneumococcal disease: Adults age 18+ with invasive pneumococcal disease (n = 1878) Pneumococcal vaccination Timeframe: 2001–2003 Location: USA	Retrospective chart review	Missed opportunity definition: ≥1 healthcare encounter (including hospitalization, ER visit, outpatient visit) in the 2 years prior to pneumococcal infection	Of 617 unvaccinated patients who were eligible for a vaccination, 566 had at least one opportunity for vaccination; during 1 year Missed opportunity =92%	Disadvantages: not limited to opportunities for vaccination at primary care setting (also included cardiologists, endocrinologists, other specialties)
Skull, et al., 2007 [12]
Purpose: To examine missed opportunities for recommended influenza and pneumococcal vaccines among hospitalized elderly patients 4772 hospitalized patients 65 and older with pneumonia vaccinations and risk factor assessment Timeframe: April 2000–March 2002 Location: Australia	Self-reported survey of previous hospitalizations and number of doctor visits and provider-confirmed vaccination records	Missed opportunity = provider-subject encounter: doctor visit in the year before hospitalization (or a number of visits, each is a missed opportunity) and/or a hospitalization to the same hospital in the past 5 years	Mean estimate of visits is 11.7 per year (range 0–20); 99.8% of unvaccinated patients had at least one missed opportunity within a year. Influenza – 99.6% missed opportunity with at least one visit PPV – 99.8% missed opportunity with at least one visit in 1 year for flu and 5 years for PPV	The study was conducted in a hospital in Australia; only patients with pneumonia were included; encounters are self-reported on a range scale with increment of 5 (0–4, 5–19, 10–14, 15–19, 20 and more) for last year and yes/no for 5 previous years; automated prompts for providers are recommended as a potential solution in discussion.
Fontanesi, et al., 2004 [7]
The study used critical path analysis to understand operational factors involved in influenza vaccinations in ambulatory care 16 ambulatory care settings, 666 encounters influenza vaccinations, visits types, OCPE-S used to encode all encounters Timeframe: October 2001–January 2002 Location: USA	Prospective/observational - OCPE-S was used by visit observers to document all activities of the visit and encode all encounters	Visits that resulted in vaccination or did not (missed opportunity visits)	62% of patients were vaccinated; 92 (out of all 243 scheduled) visits were missed opportunity (38% missed opportunity); 56% of visits with incomplete sequence of clinical events did not result in vaccinations; seven clinical factors combined predicted 93% vaccinations	A diagram of best pathway to result in 93% vaccinations and pathways leading to missed opportunity is provided, may be useful in QI and education strategies.
Maurer, et al., 2009 [10]
Purpose: To investigate the impact of reducing missed opportunities to vaccinate adults against influenza. US adults (n = 5067) from a national survey by Knowledge Networks in Menlo Park, CA. Influenza vaccine Timeframe: March 4–7, 2009 Location: USA	Retrospective data analysis of a survey of a national sample of US adults	Missed opportunity calculated as number of unvaccinated patients with at least 1 health care provider visit between October and December 2008 with or without accounting for the patient’s willingness to be vaccinated. Estimated numbers of vaccinated and unvaccinated adults were estimated by scaling up estimated vaccination and missed opportunity rates and disease prevalence.	This method estimates 53 million health care visits between October and December, 2008, but unvaccinated for influenza. Missed opportunity: 14.4% of unvaccinated patients with at least one visit who are amenable to vaccinations. Vaccinating all of those patients would increase overall rate for that time period by 23.1%. Eliminating missed opportunity only among those willing to be vaccinated would result in 14.4% increase.	Limitations: Vague description of methodology. Influenza only. Does not have a detailed description of missed opportunity calculation.

Abbreviations: VA Veteran’s Administration; PPV pneumococcal polysaccharide vaccine; USA United States of America; UK United Kingdom; ER emergency room; OCPE-S Observational Checklist of Patient Encounters-Seniors