NCHS July 11, 2006

NCHS July 11, 2006

Influenza Immunization in Nursing Homes: Who Does Not Get Immunized and Whose Status is Unknown

Jill A. Marsteller, PhD, MPP, Ronald Tiggle, PhD, Robin Remsburg, PhD, Abigail Shefer, MD and Barbara Bardenheier, MPH, MA

National Center for Health Statistics and the National Immunization Program

of the Centers for Disease Control and Prevention

NCHS July 11, 2006

Context

Some 32,400 influenza-related deaths among those >65 annually between 1990 and 1999

Particular risk for exposure in nursing homes

But… Fifteen percent of nursing home residents

were unimmunized for influenza in 1999 Nineteen percent had unknown

immunization status

NCHS July 11, 2006

Objectives

To analyze, in a nationally representative sample (the NNHS)

… both the resident AND facility characteristics associated with

… not receiving influenza immunization

… AND with unknown influenza immunization status

NCHS July 11, 2006

Methods

Influenza immunization among nursing home residents >65 from the 1999 National Nursing Home Survey

7,194 residents living in 1,423 facilities Multinomial logistic regression

Three-level outcome ‘Received immunization’ is referent group Used SAS and SUDAAN

NCHS July 11, 2006

Dependent Variable

“During the past 12 months, has [the resident] had an influenza vaccination at this facility or any other location?” The measure has three response categories: “yes,” “no,” or “unknown.”

Facility staff check all relevant records when responding

A survey response of unknown is marked if there is no evidence in any records of the

resident’s immunization status if the record states that status is unknown

NCHS July 11, 2006

Independent Variables Resident

characteristics pneumococcal

immunization age length of nursing

home stay primary payment

source level of care high-risk diagnosis

Facility characteristics number of beds Medicare/Medicaid certification ownership membership in a chain metropolitan statistical area geographic region assesses immunization status

upon admission organized immunization program records immunization status in

the medical record requires staff to be immunized

NCHS July 11, 2006

Significant Variables for No Immunization v. Yes Characteristics Referent   ORs (95% CI)

Age >85 65-74 1.37 (1.09-1.73)*

75-84 1.16 (0.98-1.37)

Level of Care Skilled Residential 2.33 (1.54-3.53)*

    Intermediate 1.07 (0.87-1.32)

Length of Stay >6 months <6 months 3.59 (3.01-4.30)*

Pneumococcal Immunization Yes No 8.24 (6.50-10.44)*

Unknown 3.16 (2.46-4.07)*

Certification Both Medicare & Medicaid

Medicare-only 0.79 (0.39-1.62)

    Medicaid-only 0.53 (0.36-0.77)*

    Non-certified 0.56 (0.28-1.11)

Screens for immunization at admission Yes No 1.40 (1.10-1.78)*

Organized vaccination program  Yes No 0.45 (0.22-0.92)*

Records immunization status in medical record Yes No 1.90 (1.01-3.58)*

Controlling for: chain, MSA/non-MSA, ownership, region, staff vaccinations, bedsize, primary payment source, race, high risk diagnosis, and eating assistance

NCHS July 11, 2006

Significant Variables for UK Immunization v. YesCharacteristics Referent   ORs (95% CI)

Length of Stay >6 months <6 months 4.38 (3.63-5.28)*

Eating Assistance Yes No 1.25 (1.06-1.48)*

Pneumococcal Immunization Yes No 0.83 (0.53-1.31)

Unknown 18.87 (14.43-24.69)*

Primary Payment Source    Medicaid Medicare 1.55 (1.18-2.03)*

    Private Insur. 1.54 (1.11-2.13)*

    Own funds 1.11 (0.87-1.42)

    All other 1.41 (0.82-2.44)

Certification Both Medicare & Medicaid

Medicare-only  0.68 (0.33-1.42)

    Medicaid-only  0.58 (0.37-0.92)*

    Non-certified  0.24 (0.09-0.66)*

Screens for immunization at admission Yes No  1.41 (1.03-1.93)*

Records immunization status in medical record Yes No  2.17 (1.05-4.47)*

Controlling for: age, level of care, chain, region, ownership, MSA/non-MSA, staff vaccinations, organized immunization program, bedsize, race, and high-risk diagnosis

NCHS July 11, 2006

Unknowns are Different Two binary logistic regressions test whether

unknowns are distinguishable from other categories Yes v. Unknown,Wald F=36.97, p<0.0001

Unknowns more likely: length of stay <6 months, unknown pneumonia vaccination, no eating assistance

Live in facilities with dual Medicare and Medicaid certification, no screening, no recording

No v. Unknown, Wald F=15.78, p<0.0001 Unknowns less likely residential care, immunized for

pneumonia, in facilities with >100 beds Unknowns more likely unknown pneumonia

vaccination, Medicare as payment source

(Long, 1997).

NCHS July 11, 2006

Discussion

Both resident and facility characteristics are associated with not being immunized and unknown immunization status

Important covariates are pneumococcal immunization status, length of stay, facility certification, screening and recording

Notably unimportant are staff vaccination policies and high-risk status of residents

Residents with unknown vaccination are statistically different from the immunized and the unimmunized

NCHS July 11, 2006

Conclusions

About 34 percent of residents did not receive immunizations in the last 12 months or had an unknown status

Results suggest Targeted education for residents, staff Facility screening for and recording immunization

Residents with unknown immunization are Too different from both those who do and do not

receive vaccinations to justify lumping categories Should be analyzed separately Current policy of not immunizing unknowns may

be appropriate