Background
Purpose of this study and hypotheses
Conceptual framework
Methods
Design and settings
Data sources and collection
Data source | Conceptual definition | Operational definition | |
---|---|---|---|
Dependent variables | |||
Fall rate | Incident reports/fall incident report database | (counts of total falls × 1000)/(total patient-days) | |
Injurious fall rate | Incident reports/fall incident report database | (counts of injury falls × 1000)/(total patient-days) | |
Covariates | |||
Hospital | As identified by each study hospital | Four hospitals served as study sites: one academic medical center (Hospital 1); 2 teaching hospitals (Hospitals 2 and 4); and one community hospital (Hospital 3). This study used 3 dummy variables to capture 4 study hospitals, instead of hospital characteristics (e.g., bed size and teaching status), to control for the variations across study hospitals. | 3 dummy variables were included in the regression model. Hospital 1 was used as a reference group; Hospital 2: 1 = Hospital 2, 0 = all other hospitals; Hospital 3: 1 = Hospital 3, 0 = all other hospitals; Hospital 4: 1 = Hospital 4, 0 = all other hospitals. When the values of Hospital 2, Hospital 3, and Hospital 4 = 0, Hospital 1 would be identified. |
Unit type | As identified by each study hospital | The unit classification of each study unit, as designated by the hospital, was identified by the designated site coordinate. The unit type included 3 categories: (1) medical, (2) surgical, and (3) medical-surgical combined. | Two dummy variables were included in the regression model. Medical units were used as the reference group (unit type 2: 1 = surgical unit, 0 = all other units; and unit type 3: 1 = medical-surgical combined unit, 0 = all other units). When the values of unit type 2 and unit type 3 = 0, medical units would be identified. |
Total nursing hours per patient-day (HPPDs) | The payroll database | As a system-centered measure, this was defined as the number of productive hours worked by nursing staff with direct care responsibilities per patient-day [15]. | Total nursing hours/total patient-days |
Percentage of the total nursing HPPDs supplied by registered nurses | The payroll database | As a system-centered measure, this was defined as the percentage of the productive nursing HPPDs worked by RNs with direct care responsibilities to the number of total productive nursing HPPDs worked by nursing staff with direct care responsibilities [15]. | (Total nursing HPPDs supplied by RNs/total nursing HPPDs) × 100% |
Patient age in percentage of patients aged ≥ 65 years | Patient management database | The percentage of all patients discharged from the study unit during the defined time period, who were ≥ 65 years. | (Sum of the years of the discharged patients in age/total discharged patients) × 100% |
Case mix index (CMI) | Patient management database | CMI value mean of all patients discharged from the study unit during the defined time period represents the average diagnosis-related group relative weight for that unit-month. The CMI value is used to define the average acuity for patients admitted to a particular hospital [26]. | (Sum of the CMI values of the discharged patients/total discharged patients) × 100% |
Percentage of patients with altered mental status | Chart review of the nursing notes at admission | The percentage of patients hospitalized at the study unit on the 15th of the first month of each quarter, who had cognitive impairment or altered mental status. The charts of 10 randomly sampled patients per study unit were reviewed. If any cognitive impairment or altered mental status was identified in the chart at admission, this patient was coded as Yes (1); otherwise, No (0) was coded. | (Number of patients with cognitive impairment or altered mental status/10) × 100% |
Percentage of patients with hearing problem | Chart review of the nursing notes at admission | The percentage of patients hospitalized at the study unit on the 15th of the first month of each quarter, who had hearing problems. The charts of a total of 10 randomly sampled patients per study unit were reviewed. If any hearing problems (with or without correction) were identified in the chart at admission, this patient was coded as Yes (1); otherwise, No (0) was coded. | (Number of patients with hearing problems/10) × 100% |
Call light use rate per patient-day | The reports generated from the call light tracking system adopted by each hospital | Patient/family-initiated calls made from the pillow speaker or call cord attached to the wall in the patient rooms are categorized as normal calls (excluding the calls initiated in the bathrooms). In this project, only normal calls were studied. The normal call count will include all the calls either cancelled at the console or at the stations of origin (i.e., the patient's room). | (Counts of normal calls/number of the covered days) × (total number of days for the mo.)/(total patient-days for the month) Due to the skewed distribution, this continuous variable was recorded into 10 equal groups and labeled in percentiles (10 = least frequent, 100 = most frequent). The recoded variable was analyzed as a continuous variable. |
Predictor Average response time to call lights | The reports generated from the call light tracking system adopted by each hospital | Patient/family-initiated calls made from the pillow speaker or call cord attached to the wall in the patient rooms are categorized as normal calls (excluding the calls initiated in the bathrooms). In this project, only normal calls were studied. The response time was defined as the time elapsed from normal call activation to call cancellation from the patient room. The response times were aggregated at the unit level for each month, and calculated by: (call light response time in seconds for all the calls made for the unit and month)/(total number of calls for the unit and month). | The average time for "Staff Response" on the reports generated from the call light tracking system was calculated as: (Sum of the call light response time for the calls in seconds)/(total call light use). Due to the skewed distribution, this continuous variable was recorded into 10 equal groups and labeled in percentiles (10 = fastest, 100 = slowest). The recoded variable was analyzed as a continuous variable. |
Data management
Data analyses
Results
Descriptive analyses
Hospitala
| ||||||
---|---|---|---|---|---|---|
Variable\Mean (SD) | All (n = 1063) | 1 (n = 750) | 2 (n = 92) | 3 (n = 56) | 4 (n = 165) | One-way ANOVA tests (p) |
Total fall rate/1000 patient-days | 4.08 (3.06) | 4.29 (3.24) | 3.87 (2.13) | 2.96 (1.96) | 3.60 (2.78) | F = 5.23** (p = 0.001) |
Injurious fall rate/1000 patient-days | .91 (1.11) | .97 (1.15) | .36 (.68) | .76 (.71) | 1.01 (1.17) | F = 9.22** (p < 0.001) |
Total productive nursing hours/patient-day | 9.23 (2.23) | 10.02 (2.09) | 5.17 (.99) | 9.05 (.73) | 8.30 (.66) | F = 217.19** (p < 0.001) |
Percentage of productive nursing hours provided by RNs | 72.90% (8.95) | 76.82% (6.82) | 58.37% (2.83) | 58.87% (2.85) | 68.05% (4.36) | F = 413.00** (p < 0.001) |
Percentage of patients aged ≥ 65 years | 35.93% (16.40) | 30.13% (13.53) | 66.58% (9.18) | 47.70% (7.75) | 38.10% (8.28) | F = 263.99** (p < 0.001) |
Average CMI value | 1.76 (.72) | 1.95 (.78) | 1.30 (.24) | 1.52 (.35) | 1.31 (.26) | F = 59.36** (p < 0.001) |
Percentage of patients with altered mental status at admission | 9.93% (11.91) | 7.18% (8.71) | 25.11% (16.14) | 21.61% (19.33) | 8.39% (7.16) | F = 106.94** (p < 0.001) |
Percentage of patients with hearing difficulties at admission | 11.33% (10.96) | 13.08% (11.19) | 10.87% (10.96) | 8.57% (9.42) | 5.16% (7.59) | F = 24.93** (p < 0.001) |
Call light use rate per patient-day | 6.43 (5.32) | 6.83 (6.03) | 4.17 (2.02) | 4.78 (2.85) | 6.40 (2.55) | F = 8.72** (p < 0.001) |
Patient call light use rate/patient-day (in 10 equal groups; 10 = least frequent, 100 = most frequent) | 54.85 (28.30) | 58.20 (30.00) | 33.80 (14.96) | 40.71 (18.08) | 56.12 (21.74) | F = 27.09** (p < 0.001) |
Call light response time in sec as well as in min and sec | 798.34/ 13 min 18 sec (3909.11) | 1047.30/17 min 27 sec (4604.87) | 190.40/ 3 min 10 sec (61.35) | 186.92/3 min 7 sec (30.11) | 167.59/ 3 min 8 sec (55.49) | F = 3.50* (p = 0.02) |
Call light response time (in 10 equal groups; 10 = fastest, 100 = slowest) | 54.74 (28.60) | 58.54 (28.76) | 50.65 (27.53) | 48.93 (18.46) | 41.16 (27.80) | F = 18.26** (p < 0.001) |
Unit typea
| ||||
---|---|---|---|---|
Variable\Mean (SD) | Medical (n = 531) | Surgical (n = 166) | Med-surgical combined (n = 366) | One-way ANOVA tests (p) |
Total fall rate/1000 patient-days | 4.52 (3.14) | 3.26 (2.73) | 3.82 (2.97) | F = 13.14** (p < 0 .001) |
Injurious fall rate/1000 patient-days | 1.03 (1.13) | .74 (1.04) | .81 (1.09) | F = 6.54** (p = 0.002) |
Total productive nursing hours/patient-day | 9.59 (1.69) | 8.12 (1.47) | 9.27 (3.05) | F = 26.62** (p < 0 .001) |
Percentage of productive nursing hours provided by RNs | 72.87% (6.89) | 71.80% (12.49) | 73.45% (9.61) | F = 1.94 (p = 0.14) |
Percentage of patients aged ≥ 65 years | 39.09% (18.84) | 35.90% (10.35) | 31.28% (13.64) | F = 22.98** (p < 0 .001) |
Average CMI value | 1.87 (.84) | 1.88 (.46) | 1.52 (.56) | F = 26.15** (p < 0 .001) |
Percentage of patients with altered mental status at admission | 10.19% (11.26) | 7.53% (8.42) | 10.77% (14.02) | F = 4.32* (p = 0.01) |
Percentage of patients with hearing difficulties at admission | 12.53% (11.76) | 8.92% (10.45) | 10.83% (9.75) | F = 7.29** (p = 0.001) |
Call light use rate/patient-day | 6.00 (3.11) | 5.85 (2.70) | 7.29 (7.98) | F = 7.39** (p = 0.001) |
Patient call light use rate/patient-day (in 10 equal groups; 10 = least frequent, 100 = most frequent) | 53.20 (28.85) | 51.02 (22.53) | 58.96 (29.41) | F = 6.34** (p = 0.002) |
Call light response time in sec as well as in min and sec | 599.33/ 9 min 59 sec (3359.26) | 548.26/ 9 min 8 sec (1385.52) | 1196.54/ 19 min 57 sec (5183.10) | F = 2.86 (p = 0.06) |
Call light response time (in 10 equal groups; 10 = fastest, 100 = slowest) | 54.24 (28.54) | 52.55 (29.16) | 56.44 (29.68) | F = 1.19 (p = 0.30) |
Testing research hypotheses
R2
| Adjusted R2
| F change | Significance | |
---|---|---|---|---|
Initial model summary (covariates only)
| 0.08 | 0.07 | 7.36 |
p < 0.001** |
Final model summary (covariates and predictor)
| 0.10 | 0.09 | 24.24 |
p < 0.001** |
Final model
| ||||
ANOVA |
Sum of squares (df)
|
Mean square
|
F value
|
Significance
|
Regression | 975.75 (13) | 75.06 | 8.81 |
p < 0.001** |
Residual | 8939.23 (1049) | 8.52 | ||
Total | 9914.98 (1062) | |||
Covariates and predictor
|
Standardized coefficient (β)
|
t
|
Significance
| |
(Constant) | -- | 8.06 |
p < 0.001** | |
Hospital 1 (the reference group) | -- | -- | -- | |
Hospital 2 (1 = Yes, 0 = No) | -0.11 | -2.06 | 0.04* | |
Hospital 3 (1 = Yes, 0 = No) | -0.22 | -5.60 |
p < 0.001** | |
Hospital 4 (1 = Yes, 0 = No) | -0.05 | -1.30 | 0.19 | |
Medical unit (the reference group) | -- | -- | -- | |
Surgical unit (1 = Yes, 0 = No) | -0.12 | -3.16 | 0.002** | |
Medical-surgical combined unit (1 = Yes, 0 = No) | -0.09 | -2.60 | 0.010* | |
Total productive nursing hours/patient-day | 0.13 | 3.05 | 0.002** | |
Percentage of productive nursing hours provided by RNs | -0.30 | -6.21 |
p < 0.001** | |
Percentage of patients aged ≥ 65 years | -0.07 | -1.64 | 0.10 | |
Average CMI value | 0.06 | 1.75 | 0.08 | |
Percentage of patients with altered mental status at admission | 0.10 | 2.77 | 0.006** | |
Percentage of patients with hearing difficulties at admission | 0.01 | 0.26 | 0.80 | |
Call light use rate/patient-day (in 10 equal groups; 10 = least frequent, 100 = most frequent) | -0.07 | -2.12 | 0.03* | |
Call light response time (in 10 equal groups; 10 = fastest, 100 = slowest) | 0.15 | 4.92 |
p < 0.001** |
R2
| Adjusted R2
| F change | Significance | |
---|---|---|---|---|
Initial model summary (covariates only)
| 0.07 | 0.06 | 6.97 |
p < 0.001** |
Final model summary (covariates and predictor)
| 0.08 | 0.07 | 6.78 | 0.009** |
Final model
| ||||
ANOVA |
Sum of squares (df)
|
Mean square
|
F value
|
Significance
|
Regression | 104.50 (13) | 8.04 | 6.99 |
p < 0.001** |
Residual | 1206.50 (1049) | 1.15 | ||
Total | 1310.99 (1062) | |||
Covariates and predictor
|
Standardized coefficient (β)
|
t
|
Significance
| |
(Constant) | -- | 5.17 |
p < 0.001** | |
Hospital 1 (the reference group) | -- | -- | -- | |
Hospital 2 (1 = Yes, 0 = No) | -0.11 | -2.01 | 0.045* | |
Hospital 3 (1 = Yes, 0 = No) | -0.10 | -2.37 | 0.02* | |
Hospital 4 (1 = Yes, 0 = No) | 0.08 | 1.79 | 0.07 | |
Medical unit (the reference group) | -- | -- | -- | |
Surgical unit (1 = Yes, 0 = No) | -0.11 | -2.91 | 0.004** | |
Medical-surgical combined unit (1 = Yes, 0 = No) | -0.09 | -2.69 | 0.007** | |
Total productive nursing hours/patient-day | 0.14 | 3.12 | 0.002** | |
Percentage of productive nursing hours provided by RNs | -0.20 | -4.09 |
p < 0.001** | |
Percentage of patients aged ≥ 65 years | -0.13 | -3.19 | 0.001** | |
Average CMI value | 0.07 | 1.85 | 0.07 | |
Percentage of patients with altered mental status at admission | 0.05 | 1.48 | 0.14 | |
Percentage of patients with hearing difficulties at admission | 0.01 | 0.39 | 0.70 | |
Call light use rate per patient-day (in 10 equal groups; 10 = least frequent, 100 = most frequent) | -0.07 | -2.08 | 0.04* | |
Call light response time (in 10 equal groups; 10 = fastest, 100 = slowest) | 0.08 | 2.60 | 0.009** |