Characteristics and quality of studies

The characteristics of the 16 included studies are outlined in figure 3.1 and table 3.1. The majority were descriptive and conducted in adult settings. Generalisability was limited in eight studies as these were conducted in: (1) only one or two wards (Ho et al., 1997; Cavell &

Hughes, 1997; Taxis et al., 1999; Dean & Barber, 2000; Bruce & Wong, 2001; Franklin et al.,

2006; Franklin et al., 2007), (2) wards that received a hospital-specific intervention (Franklin et al., 2007; Franklin et al., 2006), or (3) an unknown number and type of wards (Wirtz et al., 2003).

Figure 3.1 Characteristics of 16 observational studies of medication administration errors.

Weighted font sizes have been used to illustrate approximate proportion of studies between groups that contain more than two studies. ^aOne study of parenteral administrations was included as all doses observed for intravenous (IV) doses except for one intramuscular and one subcutaneous dose. ^bThree of 12 studies were comparison studies with other countries.

In relation to the quality criteria, ten studies reported clear definitions and methods for determining the MAE rate; six did not. Specifically, the following were unclear: (1) the number of MAEs possible per dose (Ridge et al., 1995; Gethins, 1996; Conroy et al., 2007), (2) whether or not dose omissions were included in the denominator (Wirtz et al., 2003; Ridge et al., 1995; Gethins, 1996; Taxis & Barber, 2003b; Conroy et al., 2007), and (3) whether or not

‘extra doses’(as defined by Allan and Barker, 1990), were included in the denominator (Wirtz et al., 2003; Ridge et al., 1995; Hartley & Dhillon, 1998; Taxis & Barber, 2003b; Conroy et al., 2007). Participants were told the study objectives in three studies, were not informed in three and partially informed in ten.

Observers were pharmacists in 14 studies, a pharmacist and pharmacy technician in one (Conroy et al., 2007) and a nurse in another (Kelly et al., 2011). Data were collected by one observer in nine studies, two observers in six (Dean et al., 1995; Ridge et al., 1995; Taxis et al., 1999; Dean & Barber, 2000; Franklin et al, 2006; Conroy et al., 2007), and four pharmacists in another (Franklin et al., 2007). Of the seven studies with more than one observer, one (Dean & Barber, 2000) assessed inter-observer reliability (reported in a separate paper)(Dean & Barber, 2001), one reported that “detection of medication errors was comparable between the two observers” (Dean et al., 1995), and five did not report whether or not inter-observer reliability was assessed (Ridge et al., 1995; Taxis et al., 1999;

Franklin et al., 2006; Franklin et al., 2007; Conroy et al., 2007). Potential sources of variation were explored in some studies: observations at specific times of day (Ho et al, 1997; Hartley

& Dhillon, 1998; Dean & Barber, 2000), days of the week (Ho et al., 1997; Dean & Barber, 2000), time-point of inpatient stay (Ho et al., 1997), timing of administration in relation to when the medication was prescribed (Ho et al., 1997), and nurse-specific variation (Dean &

Barber, 2000). All papers reported whether or not IV doses were studied; three studied both dose types but did not report error rates for these separately (Ridge et al., 1995; Conroy et al., 2007; Ghaleb et al., 2010). Ten papers did not specify whether adults, paediatrics, or both, were studied, however all were confirmed as being conducted in adult settings by the relevant authors.

Clinical severity of MAEs was assessed in eight studies: five (Taxis et al., 1999; Dean & Barber, 2000; Taxis & Barber, 2003b; Franklin et al., 2007; Kelly et al., 2011) used the validated method of Dean and Barber (Dean & Barber, 1999), one (Wirtz et al., 2003) used an earlier method developed by Dean (Dean, 1999), one involved an unreported number of clinical pharmacists and the researcher reaching consensus on whether each MAE was minor, moderate or major (Hartley & Dhillon, 1998), and one used the judgement of an experienced

pharmacist researcher to classify each MAE as either minor or potentially serious (Franklin et al., 2006). All severity assessments were based on potential (rather than actual) harm.

No obvious trend in MAE rates over time was identified, table 3.1. A forest plot of non-IV studies which used the same MAE definition and denominator also showed no apparent trend in MAE rates over time (figure 3.2). A scatterplot of the same studies revealed no discernible correlation between MAE rates and sample size (figure 3.3).

Figure 3.2 Forest plot of 12 reported medication administration error (MAE) rates from eight UK observational studies of non-IV doses that used the same error definition, denominator definition and error rate calculation.

Study Sample

(OEs) % MAE rate of OEs

Dean et al (1995) 2765

Cavell and Hughes (1997) (handwritten) 1206

Cavell and Hughes (1997) (computer) 1295

Ho et al (1997) 2170

Taxis and Barber (1999) 842

Dean and Barber (2000) (drug trolley) 3576

Dean and Barber (2000) (bedside locker) 2491 Franklin et al (2006) (pre web-based education) 1165 Franklin et al (2006) (post web-based education) 1282

Franklin et al (2007) (pre EPMA) 1473

Franklin et al (2007) (post EPMA) 1139

Kelly (2011) 2129

Pooled MAE rate (meta-analysis, random-effects model) 21,533

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Figure 3.3 Scatterplot of 12 reported medication administration error (MAE) rates from eight comparable UK studies of non-IV doses.

Table 3.1 Characteristics of 16 UK observational studies and reported medication

administration error (MAE) rates. *Wrong time errors were excluded from reported MAE rates where applicable.

Study Study setting Data collection Were participants told the purpose of the

Gethins 1996 1 hospital, 5 wards: 4 medical,

42 drug rounds on ward with handwritten charts (H). 35

5 weekdays on each ward in May and July 1997. All

Table 3.1 continued. Characteristics of 16 UK observational studies and reported medication administration error (MAE) rates. *Wrong time errors were excluded from reported MAE rates where applicable.

2 week period on each ward (2004/2005) each day,

acomparison study of UK and USA hospital (only UK data is presented)

b comparison study of UK and German hospital (only UK data is presented).

CICU, cardiac intensive care unit; CTS, cardio-thoracic surgery; ED, emergency department; EPMA, electronic prescribing and medication administration system; ICU, intensive care unit; IM, intramuscular; IV, intravenous; MfE, medicine for the elderly; NICU, neonatal intensive care unit; OE, opportunities for error; PICU, paediatric intensive care unit; SC, subcutaneous.