Demographic characteristics of study population

Summaries of the characteristics of the study population (the aforementioned 239 AML/APML patients) are presented in the following paragraphs, while relevant details, such as numbers and percentages, are shown in below.

4.1.1 Diagnosis

As shown on Table 4.1, the most common subtype domain of diagnosis was the AML NOS. More specifically, nearly 83% of cases were diagnosed with ‘AML NOS’, while the rest of the subtypes for AML accounted for 7.53%. In relation to APML patients, ‘APML t(15;17)(q22;q11-12)’ accounted for approximately 10% of the total cases. The distribution was in line with previous reports both in the UK and worldwide [166-169].

4.1.2 Gender

As shown in Table 4.1, 122 female patients (51.05%) and 117 male patients (48.95%) were identified in the current study. AML and APML accounted for 90.16% and 9.84%

respectively for female patients, while for male patients 89.74% and 10.26%. This result was slightly inconsistent with the results of other previous studies [167, 168, 170-172].

Generally, AML/APML was more common in men than women, but the difference was not significant [167, 168, 170-172]. It is suggested that two factors contributed to the above. Firstly, four patients that were excluded from the study because of un-obtainable notes, were all male. Secondly, a higher number of male patients was observed among the children (<18 years old) that were excluded from the study. This suggests that no significant gender differences would exist if all the patients were included.

4.1 Patient characteristics (HMRN)

100

4.1.3 Age

Age was an important risk factor for AML. According to the results of the current study, old patients (≥60 years old) were more likely to have AML/APML than young adult patients (<60 years old). However, further examination showed that the age distributions of AML and APML varied significantly. In AML patients, the incidence of AML

Table 4.1 Demographic characteristics of study population

Frequency Percentage

AML arising from transformation of MDS 10 4.18

AML arising from transformation of MPD 1 0.42

AML with adverse cellular features 32 13.39

AML with multi-lineage dysplasia 1 0.42

AML with core binding factors 10 4.18

AML inv(16)(p13;q22) 5 2.09

AML t(8;21)(q22;q22) 5 2.09

AML - probable therapy related 6 2.51

AML - probable therapy related 6 2.51

AML with MLL (11q23) rearrangement 2 0.84

AML with MLL (11q23) rearrangement 2 0.84

APML 24 10.04

APML t(15;17)(q22;q11-12) 24 10.04

Age Mean: 63.62 (19-97), SD=18.11

<60 86 35.98

At nursing residential home 6 3.19

No 50 20.92

History of antecedent haematological disorder

Yes 17 7.11

No 222 92.89

Total 239 patients

4.1 Patient characteristics (HMRN)

101

increased with age. AML patients over 75 years of age accounted for 31.8% and those between 60 and 75 for 30.13%, while younger AML patients (<60 years old) accounted for 28.03%. Unlike the distribution of AML, most of the APML patients (19 out of 24 APML patients) belonged in the young age group (18-60 years old). APML patients over 60 years of age only accounted for 20.83% of all the APML patients. This result is consistent with the results of other studies [166-169, 171].

4.1.4 Cases of fatality (percentage of death)

The percentage of death of AML/APML was very high. As shown in Table 4.1, 79%

patients died within a maximum of five years of follow-up (the median number of year of follow-up was 4 years). After cross-analysis, the relationships between the mortality rate and several patient characteristics were identified (Table 4.2).

As shown in Table 4.2, the mortality rate of AML (84.19%) was much higher than this of APML (29.17%). Moreover, older patients appeared to have poorer prognoses, both when they were diagnosed with AML and with APML. It is suggested that this could be because older patients were either less likely to respond well to the treatments or less able to undertake/tolerate the treatments as a whole. This result is also in line with the results of previous studies [166-169, 171]

Table 4.2 Mortality rate analysis

Frequency Percentage

Deprivation group 1 (most affluent) 40 21.16 74.07

Deprivation group 2 34 17.99 77.27

Deprivation group 3 49 25.93 81.67

Deprivation group 4 35 18.52 87.50

Deprivation group 5 (most deprived) 31 16.40 75.61

Diagnosis

AML NOS 168 88.89 85.28

AML with core binding factors 7 3.70 70

AML - probable therapy related 6 3.17 100

AML with MLL (11q23) rearrangement 1 0.53 50.00

APML t(15;17)(q22;q11-12) 7 3.70 29.17

Primary induction therapy

Intensive treatment with induction intent 90 47.62 64.75

Intensive treatment without induction intent 39 20.63 97.50

Support or palliative care only 60 31.75 100.00

189

4.1 Patient characteristics (HMRN)

102

Table 4.2 also shows the mortality rate results by primary induction therapy and deprivation. In regards to the primary induction therapy, the intensive treatments with induction intent (such as clinical trials or some intensive chemotherapies) provided a better prognosis for patients (lower mortality rate: 64.75%). Patients who only received supportive or palliative care had the worst prognosis (mortality rate was 100%). The results showed that AML/APML could be very fatal if left untreated or treated without induction intent.

As shown in Table 4.2, the examination of the relationship between mortality rate and deprivation, uncovered an existing trend: increasing deprivation corresponded to higher mortality rates. The difference ranged from 74.07% for the most affluent group (group 1) to 87.50% for the second most deprived group (group 4). It is worth noting that the most deprived group (group 5) was not consistent with this trend. A possible explanation was that, compared to other groups, the most deprived group contained higher percentages of APML patients with lower mortality rate, compared to AML patients (as mentioned above).

4.1.5 Place of death

“Place of death” information is a useful factor for determining the dying cost, as well as for providing a broad picture of the location AML/APML patients received dying care during the final stages of their life. Table 4.1 lists the percentages of each possible place.

Unsurprisingly, most of the patients died in hospitals (72.87%), a lower number in hospice or nursing residential homes, while only 11.70% of the patients died at home.

4.1.6 Antecedent hematological disorder and therapy related AML

Antecedent hematological disorder (AHD) and therapy related AML has been one of the most important AML/APML prognostic factors for years. In general, patients with a history of antecedent haematological disorder (MDS) or diagnosed with therapy related AML are more likely to have poor prognosis, such as lower CR rate and higher relapse rate after achieving remission [24, 173, 174]. As shown in Table 4.1, there were 17 patients (7.11%) with antecedent haematological disorders and 6 patients diagnosed with therapy related AML. Cross-analysis showed that the aforementioned results were in line with the results of previous studies.