# Medication Errors Detected in Primary Health Care after Hospital Discharge
## 3 Results
### Analysis of Medication Errors  
The mean age of the conciliated patients was 64.6 years, and most of the conciliations analyzed (57.6%) were performed in patients older than 65 years. Based on these two aspects, the patients were grouped into two age strata to perform the analysis of the medication errors: those who were younger than 65, and those aged 65 and older (Table 3). A total of 57.6% of the conciliations were performed in patients aged 65 and older, and 70.5% of the medication errors (n = 1606) were found in patients aged 65 and older, versus 29.5% (n = 672) found in patients below 65 years (Chi-squared test, \(p\) < 0.001). When analyzing the different types of medication errors, the prevalence of all of them was higher in patients aged 65 and older, being these differences statistically significant (Chi-squared \begin{table}
\begin{tabular}{l c c} \hline \hline
**Medication Error** & **n** & **\%** \\ \hline Medication omission & 1387 & 22.7 \\ Contraindicated medication & 466 & 7.6 \\ Differences in dosages & 362 & 6.0 \\ Drug interactions & 32 & 0.5 \\ Duplicated therapeutics & 31 & 0.5 \\ Total medication errors & 2278 & 37.25 \\
**Total conciliations analyzed** & **6115** & **100** \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Most reported medication errors. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Age Strata** & **n** & **\%** \\ \hline \(>\)79 & 2139 & 35.0 \\ 65–79 & 1383 & 22.6 \\ 50–64 & 1180 & 19.3 \\ 35–49 & 843 & 13.8 \\ 34–20 & 570 & 9.3 \\
**Total** & **6115** & **100** \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Distribution of patients according to their age. test). The most frequent error was the medication omission, found in 27.2% of patients 65 and older (n = 957), and in 16.6% of patients under 65 (n = 430). The following most frequent errors found were contraindicated medication, found in 10.5% of patients 65 and older and in 4.3% of patients under 65, and differences in dosages, found in 6.8% of patients 65 and older and in 4.7% of patients under 65. Regarding sex and mean age (Table 4), a total of 52.1% of the medication errors were found in men (n = 3184) and 47.9% in women (n = 2931). The mean age of the men was 65.6 years, and the mean age of the women was 63.6 years. This difference was statistically significant (Mann-Whitney test, \(p<0.05\)). The prevalence of the medication errors in the different age and sex groups (Table 5) was different (\(p<0.001\); Chi-squared test). As shown in Figure 1, the number of conciliated patients substantially increases from the 50-64 years strata. In this same age strata, and in 65-79 years, the number of men was higher but, in the strata of over 79 years, the percentage of women (35.8%) was bigger than men (34.2%). The largest number of conciliated patients were 65 years or older. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Sex** & **n** & **Mean Age** & **S.D.** & \(p\)* \\ \hline Women & 2931 & 63.6 & 20.64 & \\ Men & 3184 & 65.6 & 17.44 & \textless{}0.02 \\
**Total** & **6115** & & & \\ \hline \hline \end{tabular}  
* Mann-Whitney test.  
\end{table} 
Table 4: Mean age and sex of conciliated patients. \begin{table}
\begin{tabular}{l c c c} \hline \hline
**Medication Error** & **\textless{}65** & **\textgreater{}=65** & \(p\)* \\ \hline Medication omission & 430 (16.6\%) & 957 (27.2\%) & \textless{}0.01 \\ Contrainticated medication & 111 (4.3\%) & 355 (10.5\%) & \textless{}0.01 \\ Differences in dosages & 121 (4.7\%) & 241 (6.8\%) & \textless{}0.05 \\ Drug interactions & 4 (0.1\%) & 28 (0.8\%) & \textless{}0.01 \\ Duplicated therapeutics & 6 (0.2\%) & 25 (0.7\%) & \textless{}0.01 \\ Total & 672 & 1606 & \textless{}0.001 \\ \hline \hline \end{tabular}  
* Chi-squared test.  
\end{table} 
Table 3: Medication errors analyzed by age of patients.