Validation of Quality of Life Instruments for Cancer Patients – Colorectal Cancer (QLICP-CR) in patients with colorectal cancer in Northeast China

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide [1]. According to the latest data, there were almost 1.4 million new cases and 693,900 deaths worldwide in 2012 [1], and 376,300 new cases and 191,000 deaths in China in 2015 [2]. In China, CRC is the fifth most common cancer in men and the fourth in women, and the fifth most common cause of death from cancer in both men and women [3]. It is therefore becoming a major public health problem in China.

CRC is one of the most curable cancers [4–6], and the number of people surviving it is growing [7]. It and its treatment strongly affect quality of life (QOL) [4]. The physiological and pathological changes caused by CRC and its treatment will inevitably lead to changes in the physical function, physiological function and mental state of patients. QOL is also known to be an independent predictor of survival in CRC patients [8, 9]. A number of studies have therefore focused on QOL in patients with CRC in recent years [10–14].

Several QOL instruments for patients with CRC have been developed, such as the European Organization for Research and Treatment of Cancer (EORTC) quality of life questionnaire QLQ-C30 (Core Module), QLQ-CR38 and QLQ-CR29 (Colorectal Module) [15–17], and the Functional Assessment of Cancer Therapy – Colorectal (FACT-C) [18, 19] from the Center on Outcomes, Research, and Education (CORE). Previous studies have confirmed that the Chinese versions of QLQ-C30, QLQ-CR29 and FACT-C are valuable tools to assess QOL in CRC patients [20–22], but these instruments were originally developed for English-speaking patients. The Quality of Life Instruments for Cancer Patients – Colorectal Cancer (QLICP-CR) has therefore been developed by Chinese researchers to take account of the cultural background in China [11].

QLICP-CR was shown to be a valid way to measure QOL of CRC patients in southern areas of mainland China ten years ago [11, 23]. However, the age-standardized CRC incidence and mortality rates have increased in the last ten years [24], and are different in different areas of China [24]. China is also a big country, and regional cultures vary widely. There are five main cultural regions, northeast, northwest, Beijing-Tianjin, southwest, and Tibet [25]. This regional culture difference appears in many aspects of life. For example, the diet in the northeast is more rough and salty, while the diet in the south is small, fine and sweet. People in the northeast tend to drink more on average than those in the south [26–28]. Refined grain and alcohol consumption patterns have been linked to an elevated risk of CRC [29, 30]. Cognitions and perceptions about health and illness also vary between cultures, which in turn affects the assessment of QOL [31]. QLICP-CR measures perceptions of QOL and is dependent on culture [32], so needs to be verified in different regions before application. However, to our knowledge, there has been no assessment of QLICP-CR among CRC patients in Northeast China. This study therefore carries out this assessment.

This study was designed to evaluate the reliability, validity and responsiveness of QLICP-CR, by using it three times per patient among CRC patients who were hospitalized and received treatment in Liaoning Cancer Hospital & Institute in Northeast China. We hoped that this would provide evidence of QLICP-CR’s suitability to assess QOL of CRC patients.

This study involved 186 patients with CRC, and we received effective responses from 152 patients (effective response rate 81.72%).

Validity

The item–domain correlations for QLICP-CR are shown in Table 2. Pearson correlation analysis showed that correlation coefficients between items and their own domains ranged from 0.19 to 0.90. The correlation coefficients of items with their own domains were all greater than the coefficients with other domains.

Domain	Item (brief description)	Item–domain correlation
		PHD	PSD	SOD	SSD	SPD
Physical domain (PHD)	GPH l (Appetite)	0.76	0.38	0.22	0.35	0.11
	GPH 2 (Sleep)	0.65	0.21	0.10	0.23	0.26
	GPH 3 (Effects to Sexual life)	0.45	0.33	0.25	0.23	0.03
	GPH 4 (Effects to entertainment)	0.62	0.22	0.16	0.11	0.09
	GPH 5 (Housework)	0.78	0.25	0.21	0.20	−0.15
	GPH 6 (Ability of daily living)	0.77	0.29	0.29	0.17	−0.19
	GPH 7 (Mobility)	0.58	0.27	0.20	0.23	−0.04
Psychological domain (PSD)	GPS l (Anxiety/depression)	0.33	0.84	0.37	0.40	0.11
	GPS 2 (Dysthymia)	0.41	0.90	0.41	0.37	0.10
	GPS 3 (Dysphoria)	0.30	0.81	0.27	0.27	0.02
	GPS 4 (Disturbed by bad mood)	0.42	0.88	0.42	0.42	0.09
	GPS 5 (Worry of becoming worse of health)	0.41	0.82	0.35	0.42	0.04
	GPS 6 (Self-abasement)	0.40	0.85	0.40	0.37	0.02
	GPS 7 (Lonely)	0.40	0.81	0.41	0.33	0.04
	GPS 8 (Dread of disease)	0.32	0.87	0.38	0.40	0.06
	GPS 9 (Attention)	−0.17	0.28	−0.01	0.17	0.10
	GPS 10 (Memory)	0.24	0.62	0.30	0.34	− 0.11
	GPS 11 (Worry of becoming a family burden)	0.30	0.65	0.50	0.27	0.03
	GPS 12 (Belief overcome disease)	0.27	0.50	0.26	0.19	−0.10
Social domain (SOD)	GSO l (Family support)	0.08	0.25	0.57	−0.07	− 0.08
	GSO 2 (Friends support)	0.19	0.20	0.63	−0.01	0.01
	GSO 3 (Family role)	0.27	0.26	0.59	0.01	−0.05
	GSO 4 (Medical assurance)	0.22	0.08	0.61	0.06	−0.08
	GSO 5 (Effects to family economy)	0.14	0.40	0.55	0.16	0.03
	GSO 6 (Effects to work/social status)	0.19	0.41	0.61	0.37	−0.08
Common symptoms and side-effects domain (SSD)	GSS l (Nausea and vomiting)	0.23	0.33	0.13	0.63	0.14
	GSS 2 (Hair loss)	0.12	0.34	0.22	0.60	0.07
	GSS 3 (Mouth ulcer)	0.07	0.13	−0.02	0.44	0.16
	GSS 4 (Pain)	0.23	0.23	0.05	0.63	0.21
	GSS 5 (Weight change)	0.28	0.31	0.23	0.57	−0.05
	GSS 6 (Diarrhea)	0.17	0.20	0.01	0.59	0.46
	GSS 7 (Fatigue)	0.24	0.34	0.13	0.74	0.24
Specific domain (SPD)	SCR 1 (Difficulty in moving bowels)	0.09	0.09	0.06	0.46	0.50
	SCR 2 (Frequent bowel movements)	0.15	0.12	0.12	0.38	0.39
	SCR 3 (Watery stools frequently)	0.25	0.15	0.07	0.35	0.37
	SCR 4 (Had blood with stools)	−0.06	0.12	0.12	0.10	0.19
	SCR 5 (Feeling the urge to move bowels without actually producing any stools)	0.14	−0.01	−0.09	0.39	0.59
	SCR 6 (Diarrhea and constipation alternately)	0.29	0.18	0.06	0.45	0.47
	SCR 7 (Pain in abdomen)	0.21	0.12	0.02	0.49	0.50
	SCR 8 (Abdominal bloat)	0.24	0.13	0.01	0.47	0.47
	SCR 9 (Pain in buttocks or waist)	0.21	0.12	−0.02	0.38	0.38
	SCR 10 (Difficulty in caring for the stoma)	0.11	0.26	−0.17	0.28	0.54
	SCR 11 (Self-abasement to because of the stoma)	−0.11	0.42	−0.09	0.21	0.43
	SCR 12 (Worry of smelling stools)	−0.04	0.39	0.02	0.24	0.43
	SCR 13 (Effects to social activity by the stoma)	0.09	0.34	0.02	0.19	0.37
	SCR 14 (Inflammation around the stoma)	−0.02	0.23	0.04	0.33	0.45

Correlation coefficients for domain scores between FACT-C and QLICP-CR are shown in Table 3. FACT-C was used to evaluate the criterion-related validity. The Pearson correlation coefficients between the specific domain of QLICP-CR and the colorectal cancer subscale of FACT-C, QLICP-GM and FACT-G, and the two overall scores were 0.37, 0.77 and 0.70. Generally, the correlations between similar domains were higher than between different domains. For example, the highest correlation coefficient for the psychological domain of QLICP-CR was with the emotional well-being domain of FACT-C, at 0.75.

FACT-C	QLICP-CR
	PHD	PSD	SOD	SSD	SPD	QLICP-GM	TOT
Physical well-being (PWB)	0.33*	0.53*	0.39*	0.45*	0.01	0.59*	0.49*
Social/family well-being (SWB)	0.21*	0.35*	0.43*	− 0.11	−0.09	0.33*	0.24*
Emotional well-being (EWB)	0.42*	0.75*	0.41*	0.35*	0.10	0.73*	0.66*
Functional well-being (FWB)	0.61*	0.50*	0.43*	0.17*	− 0.07	0.60*	0.47*
Colorectal cancer subscale (CCS)	0.47*	0.36*	0.22*	0.52*	0.37*	0.51*	0.61*
Functional Assessment of Cancer Therapy – Generic Scale (FACT-G)	0.54*	0.72*	0.57*	0.29*	− 0.02	0.77*	0.63*
Total scale (TOTAL)	0.59*	0.72*	0.55*	0.38*	0.07	0.80*	0.70*

*Correlations are statistically significant (P < 0.05)

Principal components and the factor loadings of QLICP-GM are shown in Table 4. A scree plot was also provided, and the results are shown in Fig. 1. Based on Bartlett’s test of sphericity (χ² = 2633, P < 0.001) and the value of the Kaiser-Meyer-Olkin test (0.84), we used EFA of QLICP-GM with varimax rotation. Using the initial eigenvalues > 1, we extracted nine principal components. Using factor loadings above 0.50, the first principal component corresponded to most items of the psychological domain (nine items, 0.62–0.89), the second to most items of the physical domain (four items, 0.53–0.86), the third with most items of the social domain (four items, 0.55–0.81), and fourth with two items from the common symptoms and side-effects domain (0.68–0.79). The fifth principal component had only one item (0.84), from the physical domain, the sixth had three (0.56–0.82) from the common symptoms and side-effects domain, the seventh had two (0.63–0.80) from the social domain, the eighth had two (0.53–0.66) from the psychological domain, and the ninth had one item (0.75) from the common symptoms and side-effects domain. Overall, these principal components accounted for 70.21% of the cumulative variance and reflected four domains of QLICP-GM. A four-factor solution (breaking at the fourth factor) could be seen on the scree-plot diagram. The variance contribution rate of each factor gradually became smaller after the fourth factor. Three principal components were extracted from the 14 items in the specific domain of QLICP-CR, accounting for 72.26% of the cumulative variance.

Domain	Item(brief description)	Principal components
		1	2	3	4	5	6	7	8	9
Physical domain (PHD)	GPH l (Appetite)		0.53
	GPH 4 (Effects to entertainment)					0.84
	GPH 5 (Housework)		0.72
	GPH 6 (Ability of daily living)		0.86
	GPH 7 (Mobility)		0.74
Psychological domain (PSD)	GPS l (Anxiety/depression)	0.84
	GPS 2 (Dysthymia)	0.89
	GPS 3 (Dysphoria)	0.85
	GPS 4 (Disturbed by bad mood)	0.86
	GPS 5 (Worry of becoming worse of health)	0.75
	GPS 6 (Self-abasement)	0.82
	GPS 7 (Lonely)	0.79
	GPS 8 (Dread of disease)	0.83
	GPS 9 (Attention)								0.66
	GPS 10 (Memory)								0.53
	GPS 11 (Worry of becoming a family burden)	0.62
Social domain (SOD)	GSO l (Family support)			0.74
	GSO 2 (Friends support)			0.81
	GSO 3 (Family role)			0.64
	GSO 4 (Medical assurance)			0.55
	GSO 5 (Effects to family economy)							0.63
	GSO 6 (Effects to work/social status)							0.80
Common symptoms and side-effects domain (SSD)	GSS l (Nausea and vomiting)						0.56
	GSS 2 (Hair loss)						0.73
	GSS 3 (Mouth ulcer)						0.82
	GSS 4 (Pain)									0.75
	GSS 6 (Diarrhea)				0.79
	GSS 7 (Fatigue)				0.68

^aFactor loadings bigger than 0.50 were displayed

QLICP-CR is a specific QOL instrument developed for Chinese patients with CRC, and takes into account the Chinese cultural background. This study examined the reliability, validity and responsiveness of QLICP-CR in a sample of 152 CRC patients being treated in a key hospital for CRC, where nearly 99% of inpatients were from Northeast China. There was very little variability in the study population, especially compared with a previous study [11] in which 110 patients provided data on admission, only 54 of whom were available at the third measurement. The representativeness of this study population suggests that the results can be generalized to the population of Northeast China.

A Cronbach’s α coefficient exceeding the 0.70 criterion was achieved in the physical, psychological, common symptoms and side-effects and specific domains, and in QLICP-GM. The value for the social domain in this study (0.62) did not meet the criterion, which is consistent with studies on patients with breast cancer and nasopharyngeal cancer [41, 42]. An α value of between 0.60 and 0.69 is, however, generally considered acceptable [43]. Research in the south of China [11] found an α value for the common symptoms and side-effects domain of 0.63, and this was considered acceptable. Although the α value for the social domain in this study did not reach 0.7, we therefore still have reason to consider that the internal consistency of QLICP-CR is acceptable. Test–retest reliability coefficients in this study were mostly above 0.80, with the exception of the common symptoms and side-effects domain, and generally better than the findings from the south of China [11]. All our findings suggest that QLICP-CR had good reliability in measuring the QOL of CRC patients in Northeast China.

The correlations between items and their own domains were strong, and the criterion of 0.40 was fulfilled for most items, except for the ninth item of the psychological domain and several items of the specific domain of QLICP-CR, which was similar to the study in the south of China [11]. This may be because each item of the specific domain evaluated CRC-specific symptoms from a different perspective, which is expected to weaken the item–domain correlation. As a result, the item–domain correlation for this domain was not as good as the others. The fourth item of the specific domain (“Have you had blood in your stools?”) had smaller coefficients with all domains. This may be because very few people paid attention to whether there was blood in their stool. Another possible reason was that the symptom can be difficult to distinguish from symptoms of other conditions [44]. QLICP-CR was therefore considered to have good convergent validity. The correlations of all items with their own domains were greater than with other domains, which was similar to the results from south China [11]. The items were therefore considered to reflect the content of their domain, showing that QLICP-CR has good discriminant validity [21]. Correlation analysis of domain scores between FACT-C and QLICP-CR also showed good criterion-related validity. Drawing on the results of the convergent validity, discriminant validity and criterion-related validity, we conclude that QLICP-CR has acceptable validity to measure the QOL of CRC patients in Northeast China.

We also used EFA to further evaluate the construct validity of QLICP-CR. Our results showed that nine and three principal components were extracted from the 32 items of QLICP-GM and 14 items of the specific domain of QLICP-CR, which was consistent with the results of the previous study [11]. Of the nine principal components, the first four corresponded to the four domains of the QLICP-GM. The item loading of the fifth to ninth principal components were also indicative (r > 0.5). Using the principle that an item should have a higher correlation with its own domain than with others, these items were attributed to the corresponding domains. It can be seen that nine principal components reflected nine facets under four domains of QLICP-GM. The scree-plot also indicated a four-factor solution. The number of factors was determined using the Kaiser criterion and scree-plot methods. Similarly, three principal components reflected three facets of the specific domain of QLICP-CR [11]. The EFA results therefore demonstrated that QLICP-CR has a reasonable structure. This finding further confirmed the validity of QLICP-CR in CRC patients in Northeast China.

Responsiveness is the most essential property of a measuring instrument [45], and is defined as the ability to detect a clinically-meaningful change [40]. In this study, QOL of CRC patients changed significantly after treatment. There were no significant differences in the physical and social domains in the study in the south of China [11]. This suggests that QLICP-CR is more responsive in CRC patients in northern China than in the south. The values of SRM for the physical, social, and common symptoms and side-effects domains and QLICP-GM in our study were higher than in the southern research [11], but smaller for the psychological domain (0.38), the total scale (0.77) and the specific domain (0.81). The lowest value in our study, however, still reached normal levels (SRM > 0.2) and was considered acceptable. The SRM value for the specific domain was a particularly good level (0.8). All these findings indicate that QLICP-CR had good responsiveness in CRC patients in Northeast China.

The results of this study indicated that QLICP-CR was a valid QOL scale for assessing CRC patients in Northeast China. Taken together with the results of a study in the south of China, they suggest that QLICP-CR is suitable for assessing QOL of patients with CRC in both northeast and south China. There are a number of cultural differences between northeast and south China, but this scale did not seem to be greatly affected by the differences. QLICP-CR therefore had strong stability and high credibility. In the future, it is recommended that this scale should be used when evaluating QOL in Chinese patients with CRC.

This study had some limitations. Patients were only sampled from the hospital with the highest level of diagnosis and treatment of CRC in Northeast China. We wanted to keep sampling relatively feasible and accessible in the first study in the region, so we did not focus on the lower-level hospitals. For more rigorous results, a further study covering more hospitals would be necessary.

This study was the first to our knowledge to evaluate the reliability, validity and responsiveness of QLICP-CR in CRC patients in northeast China. Our results showed that the QLICP-CR was a reliable, valid and sensitive instrument to use to assess the QOL of these patients.